Non-immune Mediated Cutaneous Drug Reactions

00:01 Let's take a look at the first group first. The first example of a non-immune mediated acute cutaneous drug reaction I'd like to go over is idiosyncratic.

00:10 These are basically just inherited enzyme deficiencies that lead to potentially cutaneous reactions. This is a good example of the inherited enzyme deficiency known as alcohol dehydrogenase deficiency that is common to folks of Asian descent. Basically, a patient who consumes alcohol and lacks this enzyme will lead to an accumulation of aldehyde, which manifests with this alcohol flush reaction that we're seeing in the far right here. The next non-immune mediated type of acute cutaneous drug reaction is the cumulative type.

00:41 This is basically a dose-dependent phenomenon, where as long as you continue to take a medication, there are manifestations that will emerge in the skin. And the classic example of this is amiodarone.

00:51 When you consume amiodarone for months to years, you can develop this slat gray pigmentation in the skin. Then there's the photosensitivity type.

01:00 This is basically a combination between a drug that you ingest and exposure to sunlight. And a good example is shown here with porphyria cutanea tarda. Folks who have porphyria cutanea tarda, if they ingest, say, iron, if they're then exposed to sunlight, can develop this florid reaction here on the hands, with some bullous formation, vesicles, etc. And lastly, irritant type.

01:24 An irritant is a non-immune mediated reaction.

01:27 It's basically caused by topically applied drugs that are simply somewhat toxic to the skin or irritating to the skin.

01:33 A good example of that would be someone who applies 5-fluorouracil cream to the hands.