Erythema multiforme is a skin immune reaction that an infection or medication can trigger. Its name combines the Latin “erythema” (redness), “multi” (many), and “forme” (shapes) and describes the main symptom, which is a rash on the body where each mark resembles a bullseye.
Erythema multiforme can affect people of any age, with children representing 20 percent of cases. However, it most commonly occurs in young adults between 20 and 30 years old. It is more prevalent in men, affecting five men for every one woman.
Erythema multiforme can be minor or major. Erythema multiforme minor is usually a mild condition that causes a skin rash. Erythema multiforme major can be more severe and typically requires more extensive treatment.
Erythema multiforme is a skin immune reaction that develops in response to infection but can sometimes occur as a result of medication.
What does it look like?
Erythema multiforme minor presents as a bulging, rash-like lesion that is red, pink, purple, or brown.
It is usually circular, less than 3 centimeters in size, and similar to a bullseye in appearance. The outermost circle has a well-defined border, while the center may be a blister.
People may think erythema multiforme major looks similar to erythema multiforme minor. However, the most significant difference in the major type is the amount of mucus and the size of the affected areas.
The rash is still bullseye-shaped in the major type, but it may be slightly larger, and the circles may run into each other. The lesions are more likely to blister and burst, and these areas of skin may be sore and oozing. Depending on their location, the lesions may also produce mucus.
With erythema multiforme major, at least two areas on the body will typically have lesions with mucus. One of these areas is often the mouth.
Where does it appear?
Erythema multiforme minor may affect the feet, face, ears, or palms and backs of the hands. It often presents initially on the hands or feet before moving toward the torso.
Erythema multiforme major may occur in the same areas, but it can also affect the mouth, lips, throat, eyes, and genitals. The lesions in these areas will usually contain mucus.
Other symptoms
A person with erythema multiforme may also experience the following symptoms:
- a cough and difficulty breathing that are signs of the infection causing the condition
- a fever or body temperature of 38°C or higher
- a general feeling of being unwell, sometimes before the rash appears
- joint pain and swelling
- painful lesions if mucus is present
Most erythema multiforme lesions are not painful, although some people may experience a burning sensation. However, lesions with mucus, such as those on the mouth, throat, genitals, or eyes, can be painful.