Exanthematous drug eruption (EDE; also known as morbilliform drug eruption) is the most common of all medication-induced drug rashes. It consists of red macules and papules that often arise on the trunk and spread symmetrically to involve the proximal extremities. In severe cases, lesions coalesce and may lead to erythroderma. The palms and soles may also be involved. Pruritus is a common complaint. While most individuals are afebrile, a low-grade fever may occur in more severe reactions. Onset is usually between 4 and 14 days after initiating a medication. The time to eruption may be shorter if the individual had previously been sensitized to the triggering medication. The eruption may occur even when the offending medication has already been discontinued.

EDE is most commonly seen with the use of antibiotics (penicillins and sulfas), allopurinol, phenytoin, barbiturates, chlorpromazine, carbamazepine, gold, d-penicillamine, captopril, naproxen, and piroxicam, but many other drug culprits have been reported, including older and newer chemotherapeutic agents, including from immunotherapies and targeted therapies (referred to as "maculopapular eruption" in the oncologic literature). Immunosuppression may play a role in the risk of developing a drug eruption, as there is a 10- to 50-fold greater risk of developing an exanthematous eruption to sulfamethoxazole in HIV-infected individuals.

Related topics: cutaneous adverse effects of BRAF inhibitors, cutaneous adverse effects of immune checkpoint inhibitors, cutaneous adverse effects of mTOR inhibitors