Medicines for Erythema multiforme

What it is

Erythema multiforme is a skin reaction that causes a distinctive rash, usually as a reaction of the immune system to an infection or, less commonly, to a medicine. The most common trigger is infection, particularly the herpes simplex virus (which causes cold sores); other infections (such as some bacterial or other viral infections) and, less often, certain medicines can also trigger it. It can affect people of any age but is more common in young adults. The characteristic feature of erythema multiforme is its rash, which typically appears as raised spots that develop into "target" or "bullseye" lesions — round patches with a darker or blistered centre surrounded by paler and then redder rings, looking like a target. The rash often starts on the hands and feet (and the arms and legs) and can spread; it may be itchy or cause a burning feeling. Most cases are mild (erythema multiforme minor), with the rash being the main feature, sometimes with mild general symptoms, and it usually clears up on its own over a couple of weeks or so, often without specific treatment. However, there is a more severe form (erythema multiforme major) that also affects the mucous membranes — such as the mouth, eyes, and genitals — causing sores and more significant illness, which needs medical attention. Erythema multiforme is also important to distinguish from rare but serious severe skin reactions (such as Stevens-Johnson syndrome, which is a medical emergency). For most people, though, erythema multiforme is a self-limiting condition that settles on its own, with treatment aimed at any symptoms and the underlying trigger; and for those who get recurrent episodes (often linked to recurrent cold sores), managing the trigger can help. The key messages are that erythema multiforme is usually a mild, self-limiting skin reaction (often triggered by cold sore infection) with distinctive target-shaped spots, that a more severe form affecting the mouth, eyes, and genitals needs medical care, and that recurrent cases linked to cold sores can be managed.

How it is treated

Erythema multiforme is usually mild and self-limiting, so management involves treating any symptoms, addressing the underlying trigger, and recognising and treating the more severe form; recurrent cases can be managed by addressing the trigger. For the common mild form (erythema multiforme minor), the rash usually clears on its own over a couple of weeks or so, so treatment focuses on relieving symptoms and, where relevant, the trigger: simple measures for any itching or discomfort (such as soothing treatments, and antihistamines for itching if advised); treating or managing the underlying trigger where identified — for example, if it is linked to the herpes simplex virus (cold sores), and particularly for recurrent episodes, antiviral treatment may be used or considered; and reviewing any medicine that may have triggered it. It usually resolves without scarring. It is important to recognise and seek medical care for the more severe form (erythema multiforme major), which affects the mucous membranes (the mouth, eyes, and genitals), causing sores and more significant illness (such as difficulty eating or drinking, eye involvement, and feeling unwell) — this needs medical assessment and treatment, which may include hospital care and supportive treatment, and eye involvement in particular needs specialist attention. It is also important to distinguish erythema multiforme from rare but serious severe skin reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis (which are medical emergencies, often triggered by medicines, with widespread blistering and skin peeling and severe illness) — so a severe, widespread, blistering rash with mucous membrane involvement and feeling very unwell needs urgent assessment. For people who have recurrent erythema multiforme, which is often linked to recurrent cold sore (herpes simplex) infections, identifying and managing the trigger — for example with antiviral treatment to prevent recurrent cold sores — can reduce the episodes, and this is discussed with a doctor. It is worth seeing a doctor for a diagnosis if erythema multiforme is suspected, particularly to confirm it, assess the severity, identify any trigger, and exclude more serious conditions. The reassuring messages are that erythema multiforme is usually a mild, self-limiting skin reaction (often triggered by cold sore infection) that clears on its own, that symptoms and triggers can be managed, and that recurrent cases can often be reduced by managing the trigger — while the more severe form, and any severe blistering rash with mucous membrane involvement and feeling very unwell, need urgent medical care.