Symptoms of drug eruption can vary and may include itching, pruritus, burning, or frank skin pain. Symptoms usually correlate with the severity of the reaction. Skin pain is associated with severe reactions and may be a harbinger of toxic epidermal necrolysis (TEN)/Stevens–Johnson syndrome (SJS). Drug reactions vary in their clinical presentation. In most cases, they occur within 3 weeks of beginning therapy. In some instances, such as penicillin eruptions in previously sensitized patients, the reaction can begin within 1 day of administration.

Urticarial and maculopapular eruptions are the most common eruptions (Fig. 17-1). Bullous reactions and erythema multiforme are less common (Figs. 16-1 and 16-2). Fortunately, palpable purpura (cutaneous vasculitis) (Fig. 62-1) and TEN/SJS (Figs. 31-1, 31-2 and 31-2) are rare. Some of the more common offending drugs are penicillins, cephalosporins, sulfonamides,
phenytoin, phenobarbital, allopurinol, nonsteroidal anti-inflammatory drugs, and gold.