Erythema Nodosum

00:01 Our topic now brings us to erythema nodosum.

00:06 Right off the bat, I’m just going to tell you what’s happening with nodosum.

00:08 We’ve seen this a few times already.

00:10 Now, we’re just going to summarize what’s actually happening in dermatology.

00:14 Most commonly, it would be located on the anterior aspect of the legs down by the shin.

00:18 Can you go down there for me, please, and picture that? And upon palpation, this hurts, it hurts.

00:25 This is also known as panniculitis.

00:27 Welcome to erythema nodosum.

00:30 Involves the septa between the fat lobules.

00:34 I’m going to stop here for one second.

00:36 So, if you were to take a look at the anterior aspect of the shin or the shin in general, and you notice there is erythema and it’s painful and maybe a little bit of yellow discoloration, which is not uncommon, this is because it’s involving the septa between the fat lobule.

00:53 Usually idiopathic.

00:54 However, there is a long list of causes, long list.

00:57 I can’t just say that it’s caused by sarcoidosis.

01:01 I cannot just say that it’s caused by coccidioides.

01:04 I can tell you that it’s caused by whole -- or should I say it’s a sequelae or manifestation that you’re going to find with the whole host of systemic fungal infections or infections in general.

01:15 May be non-infectious such as sarcoidosis.

01:19 So may be secondary to inflammation including infections, coccidioides, Histoplasma, blastomycosis, autoimmune diseases, maybe medications, and maybe hormonal, perhaps, oral contraceptive pills.

01:33 What are you paying attention to with erythema nodosum? You’re down by the shin, and apart from the erythema, there might a lipid or yellow type of appearance, and it’s painful.

01:45 Another name for this is panniculitis.

01:49 Morphology: Tender, subcutaneous nodule on the anterior shin, most commonly.

01:55 Could you find this on other locations? Sure, you can, but go with what’s most common, I beg of you.

02:01 Morphology.

02:02 Take a look at the shin of your patient.

02:05 Raised, erythematous, painful nodule on the anterior shin.

02:11 As soon as you hear this, you know that you’re looking for an underlying cause, right? That’s your clinical approach.

02:17 So, it’s not like you’re seeing this and you’re treating the erythema nodosum.

02:20 That would only be symptomatic.

02:22 I mean, what you’re really going after is, wow, what’s the underlying disorder of my patient that is then resulting in such a manifestation? Pathology: Inflammation involving the subcutaneous fat.