Dapsone-induced methemoglobinemia and hemolysis in a woman without G6PD deficiency presenting with idiopathic urticaria.

BACKGROUND: The appearance of bite cells associated with methemoglobinemia can be caused by oxidizing drugs such as dapsone in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency or high drug serum levels. Bite cells are often pathognomonic for oxidant injury in patients with G6PD deficiency and suggest active hemolysis. CASE PRESENTATION: We report a case of a woman with no prior history of G6PD deficiency who presented with anemia, methemoglobinemia and bite cells on peripheral blood smear after dapsone therapy for new onset idiopathic urticaria. Laboratory tests for G6PD, blood count and liver function were within normal limits prior to initiation of therapy. During the patient's hospital course, moderate methemoglobinemia and anemia were identified despite mildly increased serum G6PD level. These pathologies were reversed upon stopping dapsone therapy. CONCLUSION: This case highlights the potential for therapeutic levels of dapsone to induce side effects in patients without G6PD deficiency and highlights the importance of routine blood monitoring for anemia and hemolysis during the course of drug therapy.

Seasonal Onychomadesis of the Great Toes.

Onychomadesis occurs when the proximal nail plate becomes unattached to the underlying structures. When only one or a few nails are involved, the cause is usually physical trauma. A 23-year-old female presented with a 4-year history of recurrent onychomadesis involving her bilateral great toes that occurred during the springtime. While recurrent trauma from winter shoes or athletic activities may be a contributing factor, our patient was convinced that wearing tight-fitting socks during winter nights was the primary pathophysiologic process. By wearing socks only during the days and decreasing the amount of time the nails spent traumatized due to pressure, the patient's recurrent condition was eliminated.

The triad of pruritus, xanthomas, and cholestasis: Two cases and a brief review of the literature.

When encountered in children, xanthomas are most commonly associated with a group of disorders known as familial hyperlipidemias. Aside from cosmetic concerns, these xanthomas are typically asymptomatic, but when generalized pruritus is a prominent associated symptom, clinicians should consider a different set of diagnoses that includes cholestasis of the liver. In this article we present two illustrative cases of children with cholestatic disease, pruritus, and xanthomas and discuss other disorders that may include this triad.