by Kimberly Allen, RN
Erythema multiforme is a fairly common skin disorder that generally affects children and adults between 20 to 40 years of age. It is also more common in males than females. It appears to affect people of all racial and ethnic groups regardless of socio economic status and it doesn’t appear to run in families.
Erythema multiforme is believed to be a hypersensitivity reaction. This reaction can occur in response to either an infection or medication. The most common cause of erythema multiforme is the herpes simplex virus which is responsible for over half of the cases. However, in children the megaplasma pneumonieae is more commonly found to be the cause. Fungal infections are also frequently the cause of erythema multiforme in children. Some medications can also cause a hypersensitive reaction leading to the development of erythema multiforme. However the hypersensitive reaction to medications tends to be much more severe, even life threatening in some cases. The medications most commonly associated with this type of erythema multiforme include antibiotics like the penicillin’s, including amoxicillin and ampicillin, and the sulfonamides as well as tetracycline’s, certain anticonvulsants used to treat seizure disorders, and NSAID’s. There have also been reports that erythema multiforme has also been linked to some of the newer medications like Humira.
Erythema multiforme can also be recurrent. Recurrent erythema multiforme is usually caused by a reactivation of herpes simplex virus one and/or two. Researchers found the geno type of HSV1 in approximately 66.7% of the cases of erythema multiform that were herpes associated, while 27.8% had the geno type for HSV2 and 5.6% had both. While these statistics give an indication of the prevalence of the herpes simplex virus in the US it is important that most people with herpes simplex virus do not develop erythema multiforme.
There are 2 types of erythema multiforme, erythema multiforme minor and erythema multiforme major. Erythema multiforme minor is much more common and is usually caused by either a bacterial infection or the herpes simplex virus. If you have this type you may feel fine, but have an uncomfortable rash. The rash usually begins as a pink to red spotty rash that has the appearance of hives. This rash usually starts on your hands and feet then spreads to your arms and legs as well as your face and upper body causing a mild itching or burning sensation. The spots then develop into whats known as “target lesions.” These lesions have a dark red center surrounded by a pale ring then a bright red outer ring. The dark red center will blister and develop a crust. This rash generally fades in 2 to 4 weeks. Erythema Major though uncommon is a much more serious form of erythema multiforme that can be life threatening. Erythema multiforme major is usually caused by a hypersensitivity reaction to a medication instead of an infection. In this type the rash consists of larger spots that tend to fuse together to create large areas of red, raised tissue that tend to blister and develop into raw, painful sores. Many people with this type will also have raw lesions inside their mouth as well as swollen crusty lips which makes if difficult to eat and drink. People with this type also have bloodshot eyes or their eyes may be dry and burn, itch or weep as well as have a hypersensitivity to light and/or blurred vision.
The first step in treating erythema multiforme is to determine the cause when possible. then if the cause is an infection the infection must be treated. If the causes is a medication the medication must be discontinued immediately. In most cases of mild erythema multiforme, treatment is not required. However, oral antihistamines and topical steroid creams are usually recommended for relief of the symptoms. For people with a recent herpes simplex virus infection, treatment with oral acyclovir can reduce the severity and duration of the lesions. For those with the more severe form of erythema multiforme, it may be necessary to stay in the hospital for more intensive care. Many with the more severe form will need strong pain medications as well as an anesthetic mouth wash to temporarily numb their mouth so they can eat. Many are placed on liquid diets and are given corticosteroids to reduce the inflammation and antibiotics to prevent infection.
Mild cases of erythema multiforme generally resolve in 2 to 3 weeks with minimal care, while the more severe cases can take 6 weeks or more to resolve.
Kimberly Allen is a registered nurse with an AND in nursing. She has worked in ACF, LCF and psychiatric facilities, although she spent most of her career as a home health expert. She is now a regular contributor to HealthAndFitnessTalk.com, dispensing advice and knowledge about medical issues and questions. You can reach her with any comments or questions at firstname.lastname@example.org.