Erosive cheilitis as an early manifestation in DRESS syndrome

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a distinct part of severe cutaneous adverse reactions (SCARs). It is characterized by fever, rash, hematologic abnormalities, lymphadenopathy, or/and different degrees of visceral organ involvement. Its diagnosis is particularly challenging due to the variability of its clinical presentations and its long latency period (2-6 weeks). Allopurinol, an uric acid-lowering drug, has been incriminated in several cases of allopurinol-induced DRESS syndrome. Through this paper, we present a case of allopurinol-induced DRESS syndrome with initial oral mucosal involvement. A 69-year-old female patient presented with an erosive cheilitis that started 1 week prior to his presentation. The cheilitis was associated with maculopapular rash and fever. She started taking allopurinol, as treatment of Gout, 6 weeks before hospitalization. The histologic findings obtained from skin biopsy were consistent with a toxic drug reaction. A complete blood count (CBC) showed a moderate eosinophilia. Alteration of renal function was also noted, and the diagnosis of allopurinol-induced DRESS syndrome was made. Systemic corticosteroid therapy was therefore started. The patient completely recovered and had been healthy for 3 years before developing a recurrence after re-challenge with allopurinol.