A 45-year-old heterosexual man of European descent presented to our hospital with a 3-day history of fever, myalgia, headache and a macular papular rash. The rash originated on his left shoulder and anterior chest wall before extending to chest, back and abdomen. The rash also involved the palmar aspect of his hands and the plantar aspect of his feet. He had a background history of dyslipidaemia. excessive alcohol consumption, gastro-oesophageal reflux disease, recurrent pancreatitis and gout. He had been taking statin medications, esomeprazole, allopurinol and creon for several years. There had been no new complementary medicines. On arrival in hospital, his heart rate was 80 beats/min; respiratory rate, 16 breaths/min; blood pressure, 140/88 mmHg; and his temperature was 37.6 degrees C. Cardiovascular, respiratory and abdominal examinations were otherwise unremarkable. Inguinal lymphadenopathy was noted on examination. A skin examination revealed an extensive macular papular rash affecting his face, trunk and limbs, with an erosion noted on his soft palate. Investigations revealed low levels of haemoglobin (124 g/L; reference interval (RI], 135-175g/L), white blood cells (2.4 x10(9)/L; RI, 4.0-11.0 x10(9)/L) and lymphocytes (0.62 x10(9)/L (1.50-3.50 x10(9)/L). His platelet count was normal (192 x10(9)/L; RI,150-450 x10(9)/L), and his C-reactive protein level was slightly elevated (8.1mg/L; RI, <8.0 mg/L). The patient reported having unprotected sex with one new female partner in the previous 3 months. On advice from the hospital's infectious diseases team, molecular testing for measles and serological testing for syphilis and HIV were performed. The patient was discharged home after 24 hours of observation with investigations pending. The day after discharge, an HIV enzyme immunoassay (EIA) screen was reactive but western blot was negative. The patient was recalled for further HIV testing, which revealed an HIV viral load of 1060 000 copies/mL. The patient was reviewed in the hospital's infectious diseases clinic 4 days later and was found to have a persisting generalised pruritic papular rash of urticarial appearance involving his trunk and proximal limbs, including his elbows and knees (Figure 1). Target lesions typical of erythema multiforme (EM) were noted on the plantar aspects of his feet, appearing red and blue centrally, with tense oedema surrounding the pale area and a well defined erythematous peripheral margin (Figure 2). A dermatologist's opinion was sought, who agreed on a diagnosis of EM secondary to acute HIV infection. The patient's rash was treated with topical steroids and oral antihistamines and abated within 1 week. Follow-up serological testing revealed a rising HIV EIA titre and positive western blot.