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. Palms, soles, and mucous membranes may also be involved. Pruritus is a common complaint. While most patients 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 patient had previously been sensitized to the triggering medication. The eruption may occur even if 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 chemotherapeutic, biologic, and immunotherapeutic (checkpoint inhibitor) agents.