Hello and welcome to the Zero to Finals podcast. My name is Tom and in this episode I'm going to be

talking to you about erythema multiformy. And you can find written notes on this topic at zero

definals.com slash eryema multiformy or in the dermatology section of the zero to finals pediatrics

book.

So let's get straight into it.

Aerithema multiforme is an erythematous rash

caused by a hypersensitivity reaction.

The most common causes are viral infections and medications.

It's also notably associated with the herpes simplex virus, causing cold

sores, and with mycoplasma pneumonia. Let's talk about the presentation. Erathema multiforme

produces a widespread itchy ery eryithematous rash. It produces characteristic target lesions. Target lesions are red rings within

larger red rings with the darkest red ring at the circle, similar to a bull's eye target.

It does not usually affect the mucus membranes, but it can cause a sore mouth, which we call stomatitis.

The symptoms tend to come on abruptly over a few days. It may be associated with other symptoms such

as mild fever, stomatitis, muscle and joint aches, headaches and general flu-like symptoms.

Let's talk about management.

The diagnosis is made clinically based on the appearance of the rash.

It's important to identify the underlying cause.

Where there is a clear underlying cause, for example a recent cold sore or treatment with penicillin, the rash may be managed supportively.

Where there is no clear underlying cause, it may be worth investigating further, for example doing a chest x-ray to look for mycoplasma pneumonia.

Most of the time, erythema multiforme is mild and resolves spontaneously within one to four weeks without any treatment or lasting effects.

Cases may be recurrent, particularly when they're associated with recurrent cold sores.

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