Erythema multiforme is a skin rash. It's caused by a hypersensitivity reaction. The reaction can be caused by many things. These include viruses, bacteria, fungi, medicines, vaccines, or food. A severe form of erythema multiforme called Stevens-Johnson syndrome (erythema multiforme major) is most often caused by medicines. This is a very rare form of erythema multiforme.
At first, the skin may have round red bumps, fluid-filled blisters, or pimples. Most of these turn into a round circle with a small dark center. The entire area of the skin may be surrounded by a white ring. The sores may cause pain, burning, or itching. They occur most often on the forearms, legs, and back of hands and feet. In more severe cases, they may happen in the mouth or on the genitals. They are not contagious.
Treatment includes finding and treating or removing the cause. If a medicine may be the cause, you will be told to stop giving it to your child. The sores will likely go away in about 2 to 6 weeks. It may take longer in severe cases. The sores may come back. Medicine to reduce pain and inflammation may be given. Depending on the cause, your child may be given antiviral or antibiotic medicines.