A 38-year-old woman with zosteriform skin lesions

Abstract

A 38-year-old white woman with no previous medical history presented to our hospital with a 7-day clinical history of skin lesions on her shoulder. She had visited Uganda for 3 weeks, where she swam in Bunyonyi Lake at the end of the first week of the trip. She remained asymptomatic until 2 weeks after her return (approximately 5 weeks after freshwater exposure), when she developed pruritic painless erythematous papules grouped on the back part of her left shoulder following the C3-C4 dermatome (Fig 1). Under clinical suspicion of cutaneous herpes zoster, oral valganciclovir was prescribed. No clinical improvement was observed, and varicella zoster virus polymerase chain reaction from a skin lesion was negative. Routine blood tests showed eosinophilia (5,200 cells/mm3, normal count below 450 cells/mm3). No parasites, cysts, or eggs were observed in excreta. Two weeks after the clinical symptoms appeared and while waiting for the results of some serological tests, a skin biopsy (Fig 2) and a specific loop-mediated isothermal amplification (LAMP) assay of the sample were performed. What is your diagnosis?