Generalized erythematous scaly rash after glucocorticoids

Abstract

A 65-years-old woman with a medical history of idiopathic throm- bocytopenic purpura and psoriasis in treatment with topical glucocor- ticoids presented with a three-month history of burning, generalized erythematous, scaly rash, and chills. A few weeks before the rash, the patient presented petechiae on her thighs due to a low platelet count (28.000 platelets per microliter), for which she started treatment with prednisone 25 mg/week. The rash was initially treated with topical ointments including clobetasol, urea, salicylic acid, ammonium lactate, and propylene glycol without improvement. The physical examination showed generalized erythroderma (Fig. 1A) from neck to feet (Fig. 1B), with thick silvery desquamation respecting the face and back of the legs (Fig. 1C), involving more than 90% of the patient’s body surface area and erythematous scaly plaques on the scalp. Laboratory test results were normal. A punch biopsy specimen obtained from an arm area showed increased keratinization at the level of the corneal layer with compact parakeratosis with abundant polymorphonuclear cells. The epidermis presented psoriasiform hyperplasia with significant spongio- sis. What is the diagnosis?