What is Erythema Multiforme Minor?
What are the signs and symptoms?
Abrupt onset of lesions with the vast majority of lesions appearing within 24 hours. These lesions progress into target lesions, which consist of circular zones of color change with evidence of damage to the skin in the central zone such as a blister or scab. Early target lesions will have a central dusky zone and a red outer zone, but may evolve to three zones of color change. Large hives are frequently misdiagnosed as erythema multiforme.
Who is at risk for Erythema Multiforme Minor?
Observed in young adults and very uncommon in childhood. There is a slight increase
in male prevalence, but no racial bias.
What causes Erythema Multiforme Minor?
Majority of children and adults with Erythema Multiforme (EM) is precipitated by Herpes Simplex Virus types I and II (cold sore/fever blister/genital herpes). A cold sore outbreak on the lip is noted in approximately 50% patients with erythema multiforme. The cold sore may precede the onset of the cutaneous lesions, occur simultaneously, or be evident after the target lesions of EM have appeared. A cold sore will typically precede target lesions of EM by 3-14 days. Other viruses that can cause EM are: mycoplasma pneumonia, herpes varicella zoster (chickenpox/shingles), adenovirus, hepatitis, HIV, CMV, and viral vaccines.
Less than 10% of cases are caused by drugs. Most commonly associated include barbiturates, NSAIDs, penicillin, sulfonamides, phenothiazines, and anticonvulsants.