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Bullous Pemphigoid and Pemphigus Vulgaris

Bullous pemphigoid and pemphigus vulgaris are two different blistering autoimmune diseases Autoimmune diseases Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides. Selective IgA Deficiency. In bullous pemphigoid, autoantibodies Autoantibodies Antibodies that react with self-antigens (autoantigens) of the organism that produced them. Blotting Techniques attack the hemidesmosomes, which connect epidermal keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions to the basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN). This attack results in large, tense subepidermal blisters. In pemphigus vulgaris, autoantibodies Autoantibodies Antibodies that react with self-antigens (autoantigens) of the organism that produced them. Blotting Techniques attack the desmosomal proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis, which connect the keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions to one another. This attack results in a more severe, potentially fatal condition with fragile, flaccid blisters, usually with significant mucosal involvement. Diagnosis is made with biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma and IF staining to identify and localize the antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions. Management involves immunosuppression with corticosteroids Corticosteroids Chorioretinitis and other steroid-sparing immunomodulatory agents.

Last updated: May 17, 2024

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Overview

Definition

Bullous pemphigoid: 

  • A non–life-threatening, chronic autoimmune disease
  • Characterized by subepithelial Subepithelial Membranoproliferative Glomerulonephritis bullae Bullae Erythema Multiforme
  • Caused by loss of adhesion Adhesion The process whereby platelets adhere to something other than platelets, e.g., collagen; basement membrane; microfibrils; or other ‘foreign’ surfaces. Coagulation Studies between the epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions and dermis Dermis A layer of vascularized connective tissue underneath the epidermis. The surface of the dermis contains innervated papillae. Embedded in or beneath the dermis are sweat glands; hair follicles; and sebaceous glands. Skin: Structure and Functions

Pemphigus vulgaris: 

  • A life-threatening, chronic autoimmune disease 
  • Characterized by intraepithelial bullae Bullae Erythema Multiforme
  • Caused by loss of adhesion Adhesion The process whereby platelets adhere to something other than platelets, e.g., collagen; basement membrane; microfibrils; or other ‘foreign’ surfaces. Coagulation Studies between keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions ( acantholysis Acantholysis Separation of the prickle cells of the stratum spinosum of the epidermis, resulting in atrophy of the prickle cell layer. It is seen in diseases such as pemphigus vulgaris and darier disease. Varicella-Zoster Virus/Chickenpox)

Epidemiology and etiology

Bullous pemphigoid Pemphigus vulgaris
Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency per year 6‒13 per 1 million 0.1‒0.5 per 100,000
Age > 60 years old 40‒60 years old
Gender Gender Gender Dysphoria predominance Women = men Women = men
Racial/ethnic bias Bias Epidemiological studies are designed to evaluate a hypothesized relationship between an exposure and an outcome; however, the existence and/or magnitude of these relationships may be erroneously affected by the design and execution of the study itself or by conscious or unconscious errors perpetrated by the investigators or the subjects. These systematic errors are called biases. Types of Biases None More common in:
  • Ashkenazi Jewish
  • Southeast Europe
  • Middle East
  • India
Etiology None have been proven, but several possible associations:
  • Drugs (particularly DPP-4 inhibitors)
  • Genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics
  • Trauma
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma therapy
  • UV light
Possible associations:
  • Drugs (most commonly penicillamine Penicillamine 3-mercapto-d-valine. The most characteristic degradation product of the penicillin antibiotics. It is used as an antirheumatic and as a chelating agent in wilson’s disease. Wilson Disease, captopril Captopril A potent and specific inhibitor of peptidyl-dipeptidase a. It blocks the conversion of angiotensin I to angiotensin II, a vasoconstrictor and important regulator of arterial blood pressure. Captopril acts to suppress the renin-angiotensin system and inhibits pressure responses to exogenous angiotensin. Hypertension Drugs)
  • Genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics ( HLA-DR4 HLA-DR4 Goodpasture Syndrome and HLA-DR14)
  • UV light
DPP-4: dipeptidyl peptidase-4
UV: ultraviolet

Pathophysiology

Both bullous pemphigoid and pemphigus vulgaris are autoimmune diseases Autoimmune diseases Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides. Selective IgA Deficiency that attack anchoring connections of the epidermal keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions.

Anatomy and physiology review

  • Desmosomes:
    • Junctional complex
    • Connect epidermal keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions to each other
  • Hemidesmosomes:
    • Similar to desmosomes
    • Anchor the basal epidermal keratinocyte Keratinocyte Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Erythema Multiforme layer to the underlying basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN)
    • Form the dermal–epidermal junction
Epidermal keratinocyte connections

Epidermal keratinocyte connections:
Desmosomes connect keratinocytes to each other, while hemidesmosomes anchor the basal layer of keratinocytes to the basement membrane.

Image by Lecturio.

Bullous pemphigoid

  • Type II hypersensitivity reaction Type II hypersensitivity reaction Type II hypersensitivity, also known as antibody-mediated cytotoxic hypersensitivity, is caused by immunoglobulin G (IgG) and IgM antibodies directed against antigens on cells or extracellular materials. The reaction leads to cytotoxic processes involving antibodies and the complement system. Type II Hypersensitivity Reaction
  • IgG IgG The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b. Hypersensitivity Pneumonitis autoantibodies Autoantibodies Antibodies that react with self-antigens (autoantigens) of the organism that produced them. Blotting Techniques attack hemidesmosomal proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis:
    • Targeted proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis: Bullous pemphigoid antigens BP180 and BP230
    • Activation of complement and mast cells Mast cells Granulated cells that are found in almost all tissues, most abundantly in the skin and the gastrointestinal tract. Like the basophils, mast cells contain large amounts of histamine and heparin. Unlike basophils, mast cells normally remain in the tissues and do not circulate in the blood. Mast cells, derived from the bone marrow stem cells, are regulated by the stem cell factor. Innate Immunity: Phagocytes and Antigen Presentation neutrophils Neutrophils Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes. Innate Immunity: Phagocytes and Antigen Presentation and eosinophils Eosinophils Granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin. Innate Immunity: Phagocytes and Antigen Presentation release Release Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane. Virology inflammatory mediators
    • Proteases Proteases Proteins and Peptides are produced → cause the epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions to separate from the dermis Dermis A layer of vascularized connective tissue underneath the epidermis. The surface of the dermis contains innervated papillae. Embedded in or beneath the dermis are sweat glands; hair follicles; and sebaceous glands. Skin: Structure and Functions → result in large, tense bullae Bullae Erythema Multiforme
  • Desmosomes connecting keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions to each other remain intact → overlying skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions is strong and taut

Pemphigus vulgaris

  • Type II hypersensitivity reaction Type II hypersensitivity reaction Type II hypersensitivity, also known as antibody-mediated cytotoxic hypersensitivity, is caused by immunoglobulin G (IgG) and IgM antibodies directed against antigens on cells or extracellular materials. The reaction leads to cytotoxic processes involving antibodies and the complement system. Type II Hypersensitivity Reaction
  • IgG IgG The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b. Hypersensitivity Pneumonitis autoantibodies Autoantibodies Antibodies that react with self-antigens (autoantigens) of the organism that produced them. Blotting Techniques attack desmosomal proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis: 
    • Targeted proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis: desmoglein Desmoglein A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical cadherins. The Cell: Cell Junctions (DSG) types 1 and 3
    • Disruption of desmosomes → epidermal layers break apart → acantholysis Acantholysis Separation of the prickle cells of the stratum spinosum of the epidermis, resulting in atrophy of the prickle cell layer. It is seen in diseases such as pemphigus vulgaris and darier disease. Varicella-Zoster Virus/Chickenpox
    • Results in fragile, flaccid bullae Bullae Erythema Multiforme that easily rupture
      • Dysfunctional skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions barrier
      • Susceptible to secondary infection
  • Hemidesmosomes remain intact:
    • Basal layer of keratinocytes Keratinocytes Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. Skin: Structure and Functions remain anchored to the basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN) → “row of tombstones” appearance on histology
Pathophysiology of pemphigus vulgaris and bullous pemphigoid

Pathophysiology of pemphigus vulgaris and bullous pemphigoid:
A: Location of desmosomes and hemidesmosomes in epidermis
B: In pemphigus vulgaris, antibodies to desmoglein result in disruption of desmosomes, causing acantholysis and blistering within the epidermis.
C: In bullous pemphigoid, antibodies against hemidesmosomal proteins result in separation of the epidermis from the dermis.

Image by Lecturio.

Clinical Presentation

Bullous pemphigoid

  • Prodromal phase (lasting weeks to months):
    • Pruritus Pruritus An intense itching sensation that produces the urge to rub or scratch the skin to obtain relief. Atopic Dermatitis (Eczema) (moderate to severe)
    • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions lesions may appear:
      • Papular
      • Eczematous plaques
      • Urticaria-like
  • Subepidermal bullae Bullae Erythema Multiforme develop: 
    • Tense (not easily ruptured)
    • Large (1‒3 cm)
    • Contain clear fluid
    • Numerous and widespread
    • Appear on normal or erythematous skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
    • Frequently affected locations:
      • Lower abdomen
      • Axillae
      • Extremity flexures
      • Inguinal folds
      • Mucosal involvement (10%‒30% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship)
  • Bullae Bullae Erythema Multiforme rupture:

Pemphigus vulgaris

Pemphigus vulgaris is characterized by bullae Bullae Erythema Multiforme with the following properties:

  • Superficial acantholytic blisters
  • Flaccid
  • Rupture very easily: 
  • Painful
  • Appear on normal or erythematous skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
  • Can occur anywhere on the body, most commonly:
    • Mucosa (almost always present):
      • Oral (often 1st site) → odynophagia Odynophagia Epiglottitis (painful swallowing Swallowing The act of taking solids and liquids into the gastrointestinal tract through the mouth and throat. Gastrointestinal Motility) → malnutrition Malnutrition Malnutrition is a clinical state caused by an imbalance or deficiency of calories and/or micronutrients and macronutrients. The 2 main manifestations of acute severe malnutrition are marasmus (total caloric insufficiency) and kwashiorkor (protein malnutrition with characteristic edema). Malnutrition in children in resource-limited countries
      • Esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy
      • Nasal mucosa Nasal mucosa The mucous lining of the nasal cavity, including lining of the nostril (vestibule) and the olfactory mucosa. Nasal mucosa consists of ciliated cells, goblet cells, brush cells, small granule cells, basal cells (stem cells) and glands containing both mucous and serous cells. Nose Anatomy (External & Internal) epistaxis Epistaxis Bleeding from the nose. Granulomatosis with Polyangiitis
      • Conjunctiva Conjunctiva The mucous membrane that covers the posterior surface of the eyelids and the anterior pericorneal surface of the eyeball. Eye: Anatomy
      • Vulva Vulva The vulva is the external genitalia of the female and includes the mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulb, and greater vestibular glands. Vagina, Vulva, and Pelvic Floor: Anatomy, vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor: Anatomy, and cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Uterus, Cervix, and Fallopian Tubes: Anatomy
      • Penis Penis The penis is the male organ of copulation and micturition. The organ is composed of a root, body, and glans. The root is attached to the pubic bone by the crura penis. The body consists of the 2 parallel corpora cavernosa and the corpus spongiosum. The glans is ensheathed by the prepuce or foreskin. Penis: Anatomy
      • Anus
    • Cutaneous:
      • Face and scalp
      • Trunk
      • Groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination and axilla Axilla The axilla is a pyramid-shaped space located between the upper thorax and the arm. The axilla has a base, an apex, and 4 walls (anterior, medial, lateral, posterior). The base of the pyramid is made up of the axillary skin. The apex is the axillary inlet, located between the 1st rib, superior border of the scapula, and clavicle. Axilla and Brachial Plexus: Anatomy
  • Secondary infection is common:

Diagnosis

Diagnosis involves checking for a Nikolsky sign Nikolsky Sign Dermatologic Examination, biopsies for routine histopathology and IF, and ELISA ELISA An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed. St. Louis Encephalitis Virus testing.

Recommended workup

  • Nikolsky’s sign → helps determine the location of the defect
    • Apply scraping pressure → look for skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions sloughing or blister rupture
    • Positive: skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions sloughing/rupture → disease within the epidermal layer
    • Negative: no skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions sloughing or rupture disease at the dermal–epidermal junction
  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions biopsies → to assess the tissue itself:
    • Ideal biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma sites:
      • Bullous pemphigoid: lesional skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
      • Pemphigus vulgaris: normal-appearing perilesional skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions (or mucosa)
    • Routine histopathology (H&E staining)
    • Direct IF testing
  • Serum testing → to detect circulating antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions
    • Indirect IF
    • ELISA ELISA An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed. St. Louis Encephalitis Virus
Comparison of test findings
Test Bullous pemphigoid Pemphigus vulgaris
Nikolsky’s sign Negative Positive
H&E staining
  • Subepidermal nonacantholytic blisters
  • Full-thickness epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions
  • Dermal inflammatory infiltrate
  • Eosinophilic spongiosis (early lesions)
  • Suprabasal acantholytic blisters
  • Row-of-tombstones appearance
  • Sparse inflammatory infiltrate in the dermis Dermis A layer of vascularized connective tissue underneath the epidermis. The surface of the dermis contains innervated papillae. Embedded in or beneath the dermis are sweat glands; hair follicles; and sebaceous glands. Skin: Structure and Functions
IF Linear staining along the basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN) Staining within the epidermis Epidermis The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of epithelium: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis). Skin: Structure and Functions in a reticular (net-like) pattern
ELISA ELISA An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed. St. Louis Encephalitis Virus Autoantibodies Autoantibodies Antibodies that react with self-antigens (autoantigens) of the organism that produced them. Blotting Techniques against bullous pemphigoid antigens BP180 and BP230 Autoantibodies Autoantibodies Antibodies that react with self-antigens (autoantigens) of the organism that produced them. Blotting Techniques against DSG-1 and DSG-3
Bullous&pemphigus

Histology findings in bullous pemphigoid and pemphigus vulgaris:
A: H&E staining in bullous pemphigoid reveals a subepidermal bulla and numerous eosinophils.
B: H&E staining in pemphigus vulgaris reveals a suprabasal acantholytic blister. Note the row-of-tombstone appearance (a layer of keratinocytes still attached to the basement membrane).

Image A: “Disease stabilization with pembrolizumab for metastatic acral melanoma in the setting of autoimmune bullous pemphigoid” by Beck, K. M., Dong, J., Geskin, L. J., Beltrani V. P., Phelps R. G., Carvajal, R. D., Schwartz, G., Saenger, Y. M., Gartrell, R. D. License: CC BY 4.0, edited by Lecturio.

Image B: “A rare presentation of pemphigus vulgaris as multiple pustules” by Yang, Y., Lin, M., Huang, S. J., Min, C., Liao, W. Q. License: CC BY 2.0, edited by Lecturio.
Immunofluorescence bullous pemphigoid & pemphigus vulgaris

Immunofluorescence findings in bullous pemphigoid and pemphigus vulgaris:
A: In bullous pemphigoid, staining of complement and antibodies occurs at the dermal–epidermal junction.
B: In pemphigus vulgaris, staining of antibodies occurs within the epidermis in a reticular (net-like) pattern.

Image A: “A 74-year-old woman with a 1-month history of itching and skin rash” by Ghosh, S., Ghosh, A. K., Collier, A. License: CC BY 2.0, edited by Lecturio.

Image B: “Pemphigus immunofluorescence” by Emmanuelm. License: CC BY 3.0, edited by Lecturio.

Management

The goal of therapy for both bullous pemphigoid and pemphigus vulgaris is to decrease autoantibody production while minimizing drug-induced side effects.

Bullous pemphigoid

  • Mainstay initial therapy: 
    • Corticosteroids Corticosteroids Chorioretinitis (topical or systemic):
      • Topical (localized disease): clobetasol Clobetasol A derivative of prednisolone with high glucocorticoid activity and low mineralocorticoid activity. Absorbed through the skin faster than fluocinonide, it is used topically in treatment of psoriasis but may cause marked adrenocortical suppression. Glucocorticoids propionate
      • Systemic (widespread disease): prednisone Prednisone A synthetic anti-inflammatory glucocorticoid derived from cortisone. It is biologically inert and converted to prednisolone in the liver. Immunosuppressants, prednisolone Prednisolone A glucocorticoid with the general properties of the corticosteroids. It is the drug of choice for all conditions in which routine systemic corticosteroid therapy is indicated, except adrenal deficiency states. Immunosuppressants
    • Niacinamide
    • Tetracyclines Tetracyclines Tetracyclines are a class of broad-spectrum antibiotics indicated for a wide variety of bacterial infections. These medications bind the 30S ribosomal subunit to inhibit protein synthesis of bacteria. Tetracyclines cover gram-positive and gram-negative organisms, as well as atypical bacteria such as chlamydia, mycoplasma, spirochetes, and even protozoa. Tetracyclines (for anti-inflammatory effect):
      • Doxycycline
      • Tetracycline Tetracycline A naphthacene antibiotic that inhibits amino Acyl tRNA binding during protein synthesis. Drug-Induced Liver Injury
      • Minocycline Minocycline A tetracycline analog, having a 7-dimethylamino and lacking the 5 methyl and hydroxyl groups, which is effective against tetracycline-resistant staphylococcus infections. Tetracyclines
  • Advanced and refractory disease:
    • Steroid-sparing immunomodulatory agents:
      • Mycophenolate Mycophenolate Immunosuppressants mofetil
      • Azathioprine Azathioprine An immunosuppressive agent used in combination with cyclophosphamide and hydroxychloroquine in the treatment of rheumatoid arthritis. According to the fourth annual report on carcinogens, this substance has been listed as a known carcinogen. Immunosuppressants
      • Dapsone Dapsone A sulfone active against a wide range of bacteria but mainly employed for its actions against Mycobacterium leprae. Its mechanism of action is probably similar to that of the sulfonamides which involves inhibition of folic acid synthesis in susceptible organisms. It is also used with pyrimethamine in the treatment of malaria. Antimycobacterial Drugs
      • Methotrexate Methotrexate An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy
      • Cyclophosphamide Cyclophosphamide Precursor of an alkylating nitrogen mustard antineoplastic and immunosuppressive agent that must be activated in the liver to form the active aldophosphamide. It has been used in the treatment of lymphoma and leukemia. Its side effect, alopecia, has been used for defleecing sheep. Cyclophosphamide may also cause sterility, birth defects, mutations, and cancer. Immunosuppressants
    • Biologic therapies: 
  • Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas: 
    • Chronic, relapsing course
    • Long-term remission Remission A spontaneous diminution or abatement of a disease over time, without formal treatment. Cluster Headaches is possible (after months to years).

Pemphigus vulgaris

  • Mainstay initial therapy:
    • Systemic glucocorticoids Systemic Glucocorticoids Glucocorticoids: prednisone Prednisone A synthetic anti-inflammatory glucocorticoid derived from cortisone. It is biologically inert and converted to prednisolone in the liver. Immunosuppressants
    • Steroid-sparing agents:
      • Rituximab Rituximab A murine-derived monoclonal antibody and antineoplastic agent that binds specifically to the cd20 antigen and is used in the treatment of leukemia; lymphoma and rheumatoid arthritis. Immunosuppressants
      • Azathioprine Azathioprine An immunosuppressive agent used in combination with cyclophosphamide and hydroxychloroquine in the treatment of rheumatoid arthritis. According to the fourth annual report on carcinogens, this substance has been listed as a known carcinogen. Immunosuppressants
      • Mycophenolate Mycophenolate Immunosuppressants mofetil
      • Dapsone Dapsone A sulfone active against a wide range of bacteria but mainly employed for its actions against Mycobacterium leprae. Its mechanism of action is probably similar to that of the sulfonamides which involves inhibition of folic acid synthesis in susceptible organisms. It is also used with pyrimethamine in the treatment of malaria. Antimycobacterial Drugs
      • Methotrexate Methotrexate An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy
  • Refractory disease:
    • IVIG IVIG Dermatomyositis
    • Cyclophosphamide Cyclophosphamide Precursor of an alkylating nitrogen mustard antineoplastic and immunosuppressive agent that must be activated in the liver to form the active aldophosphamide. It has been used in the treatment of lymphoma and leukemia. Its side effect, alopecia, has been used for defleecing sheep. Cyclophosphamide may also cause sterility, birth defects, mutations, and cancer. Immunosuppressants
  • Complications:
    • Secondary infection
    • Effects of long-term steroid use
  • Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas:
    • Often fatal without treatment
    • Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock is the leading cause of death.

Differential Diagnosis

  • Dermatitis herpetiformis Dermatitis herpetiformis Rare, chronic, papulo-vesicular disease characterized by an intensely pruritic eruption consisting of various combinations of symmetrical, erythematous, papular, vesicular, or bullous lesions. The disease is strongly associated with the presence of hla-b8 and hla-dr3 antigens. A variety of different autoantibodies has been detected in small numbers in patients with dermatitis herpetiformis. Celiac Disease: an uncommon autoimmune cutaneous eruption associated with celiac disease Celiac disease Celiac disease (also known as celiac sprue or gluten enteropathy) is an autoimmune reaction to gliadin, which is a component of gluten. Celiac disease is closely associated with HLA-DQ2 and HLA-DQ8. The immune response is localized to the proximal small intestine and causes the characteristic histologic findings of villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis. Celiac Disease: Dermatitis herpetiformis Dermatitis herpetiformis Rare, chronic, papulo-vesicular disease characterized by an intensely pruritic eruption consisting of various combinations of symmetrical, erythematous, papular, vesicular, or bullous lesions. The disease is strongly associated with the presence of hla-b8 and hla-dr3 antigens. A variety of different autoantibodies has been detected in small numbers in patients with dermatitis herpetiformis. Celiac Disease presents with intensely pruritic, inflammatory blisters on extensor surfaces. Nikolsky’s sign is negative. Diagnosis is confirmed on biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma and IF, which may show neutrophilic microabscesses Neutrophilic Microabscesses Psoriasis and IgA IgA Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory iga is the main immunoglobulin in secretions. Immunoglobulins: Types and Functions deposits in the dermal papillary tips. Management includes dapsone Dapsone A sulfone active against a wide range of bacteria but mainly employed for its actions against Mycobacterium leprae. Its mechanism of action is probably similar to that of the sulfonamides which involves inhibition of folic acid synthesis in susceptible organisms. It is also used with pyrimethamine in the treatment of malaria. Antimycobacterial Drugs and a gluten-free diet.
  • Stevens–Johnson syndrome: an immune-complex–mediated hypersensitivity reaction involving the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions and mucous membranes, commonly triggered by medications: After a flu-like prodromal phase, patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship develop erythematous macules with purpuric centers, bullae Bullae Erythema Multiforme, and skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions sloughing. Mucosal involvement is very common. Nikolsky’s sign is positive. Diagnosis is clinical, and management is supportive. Withdrawal of the causative agent is required.
  • Staphylococcal scalded skin syndrome Staphylococcal Scalded Skin Syndrome Staphylococcal scalded skin syndrome (SSSS), also known as Ritter disease and staphylococcal epidermal necrolysis, is a toxin-mediated condition caused by Staphylococcus aureus. The exfoliative toxin produced disseminates and cleaves desmoglein 1 in the epidermis, causing separation and detachment of the skin. Staphylococcal Scalded Skin Syndrome (SSSS) ( SSSS SSSS Staphylococcal scalded skin syndrome (SSSS), also known as Ritter disease and staphylococcal epidermal necrolysis, is a toxin-mediated condition caused by Staphylococcus aureus. The exfoliative toxin produced disseminates and cleaves desmoglein 1 in the epidermis, causing separation and detachment of the skin. Staphylococcal Scalded Skin Syndrome (SSSS)): a life-threatening toxin-mediated disease, primarily of young children, caused by Staphylococcus aureus Staphylococcus aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Brain Abscess: DSG-1 is cleaved, resulting in diffuse cutaneous erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion, tenderness, formation of bullae Bullae Erythema Multiforme, and superficial desquamation Desquamation Staphylococcal Scalded Skin Syndrome (SSSS) without mucosal involvement. Nikolsky’s sign is positive. Diagnosis is clinical and confirmed with culture data. Management is with antibiotics and supportive care.

References

  1. Yancey, K. B., Lawley, T. J. (2008). Immunologically mediated skin diseases. In Fauci, A. S., Braunwald, E., Kasper, D.L., et al. (Eds.) Harrison’s Internal Medicine. 17th Ed. pp. 336–338.
  2. Leiferman, K. M. (2019). Epidemiology and pathogenesis of bullous pemphigoid and mucous membrane pemphigoid. UpToDate. Retrieved February 17, 2021, from https://www.uptodate.com/contents/epidemiology-and-pathogenesis-of-bullous-pemphigoid-and-mucous-membrane-pemphigoid
  3. Leiferman, K. M. (2019). Clinical features and diagnosis of bullous pemphigoid and mucous membrane pemphigoid. UpToDate. Retrieved February 17, 2021, from https://www.uptodate.com/contents/clinical-features-and-diagnosis-of-bullous-pemphigoid-and-mucous-membrane-pemphigoid
  4. Murrell, D. F., Ramierz-Quizon, M. (2020). Management and prognosis of bullous pemphigoid. UpToDate. Retrieved February 17, 2021, from https://www.uptodate.com/contents/management-and-prognosis-of-bullous-pemphigoid
  5. Baigrie, D. (2020). Bullous pemphigoid. StatPearls. Retrieved February 17, 2021, from https://www.statpearls.com/articlelibrary/viewarticle/18699/ 
  6. Peraza, D.M. (2020). Bullous pemphigoid. Merck Manual Professional Version. Retrieved February 18, 2021, from https://www.merckmanuals.com/professional/dermatologic-disorders/bullous-diseases/bullous-pemphigoid
  7. Hertl, M., Sitaru, C. (2020). Pathogenesis, clinical manifestations, and diagnosis of pemphigus. UpToDate. Retrieved February 17, 2021, from https://www.uptodate.com/contents/pathogenesis-clinical-manifestations-and-diagnosis-of-pemphigus 
  8. Hertl, M., Geller, S. (2020). Initial management of pemphigus vulgaris and pemphigus foliaceus. UpToDate. Retrieved February 17, 2021, from https://www.uptodate.com/contents/initial-management-of-pemphigus-vulgaris-and-pemphigus-foliaceus 
  9. Ingold, C. (2021). Pemphigus vulgaris. StatPearls. Retrieved February 17, 2021, from https://www.statpearls.com/articlelibrary/viewarticle/26884/ 
  10. Peraza, D. M. (2020). Pemphigus vulgaris. Merck Manual Professional Version. Retrieved February 18, 2021, from https://www.merckmanuals.com/professional/dermatologic-disorders/bullous-diseases/pemphigus-vulgaris

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