Circular lesions spreading up the hands

There are concentric rings of reddish colour variation on the palms of the patient and moving up to the wrist (acral distribution). A few of the lesions show a central “bullseye” or target appearance.

This is erythema multiforme (EM). It is an immune-mediated reaction which can affect the skin and mucosae.

Other common places where erythema multiforme can occur are the upper arms and face. Ensure to appropriately expose the patient to assess for any other potential lesions. We are looking for the classic target lesions. 

Ask about any previous bouts of cold sores as these are a common precipitant of erythema multiforme. There may be signs of a resolving herpetic lesion. Cold sores (herpes simplex virus) may be reactivated by sun exposure. 

Whilst the most common cause of recurrent EM is herpes simplex virus type 1, many drugs can also cause erythema multiforme such as:

• Antibiotics eg, erythromycin, penicillins, tetracyclines, and sulfonamides
• NSAIDs eg, ibuprofen or aspirin 
• Antituberculosis medications eg, pyrazinamide 
• Thiazide diuretics.

It is important to take a full history to review for any other chronic conditions, such as autoimmune disease.

• Urticaria – urticaria will be more transient and is more commonly seen as multiple wheals rather than the classic target lesion.
• Viral exanthem – more of a diffuse rash spreading symmetrically and accompanies coryzal symptoms.
• Stevens-Johnson syndrome / toxic epidermal necrolysis – a much more severe diagnosis with blistering of the skin and mucosal eruptions. Patients are usually very unwell and will need intensive care involvement. 
• Fixed drug eruption – always recurs at the same site when the offending drug is used.
• Bullous pemphigoid – multiple blisters that form tense bullae.

Usually, erythema multiforme is self-limiting and the lesions fade over 2 weeks to a month. For milder rashes, patients can use topical treatments such as creams and topical corticosteroids. 

In more severe cases, patients may need admission for regular wound care and, in some cases, may require oral corticosteroids. If oral lesions are severe, enteral fluids and feeding may be required for a short period. 

Some patients can develop secondary bacterial infections and that may require oral antibiotics.

In our patient who is having recurrent attacks, we can consider giving aciclovir on a prophylactic basis and continue for at least 6 months.