Skin eruption associated with Hymenolepis nana infection

A 56‐year‐old man presented with a recurrent cutaneous eruption of the trunk, associated with itching, which had lasted for several months. Antihistamines, such as cetirizine, loratadine, and fexofenadine, and topical steroids had been used with only temporary relief. Recently, the cutaneous manifestations had become continuous and very tedious and had not responded to local or systemic treatments. The patient was a doctor of medicine, was married, and had not been taking any medications. He had travelled for scientific purposes to different areas of Italy and The Netherlands in the last 12 months. He had no animals at home and no history of fever, sweats, arthralgia, cough, dyspnea, or allergic diseases. A history of gastritis and mild hyperglycemia was present. Skin examination showed large, erythematous, slightly edematous macules and pruritic, erythematous papules densely aggregated over scattered areas of the trunk, especially on both flanks, the abdomen, and the back ( Fig. 1). The patient appeared well and no lymphadenopathy was found. 1Erythematous papules, isolated or densely aggregated over scattered areas of the trunk, associated with areas of erythema and edema Laboratory investigations showed a hematocrit of 40.2% and a white cell count of 9000/mm 3 , with 54% neutrophils, 28% lymphocytes, 4% monocytes, and 14% eosinophils. The platelet count was 233,000/mm 3 . The albumin level was 4 g/mL. The levels of urea nitrogen, creatinine, conjugated and total bilirubin, aspartate aminotransferase, alanine aminotransferase, and aldolase were normal. Serologic tests for Toxoplasma ‐ and Toxocara ‐specific immunoglobulin G (IgG) were negative. The IgE level was 226 IU/mL (normal range, 0–120 IU/mL). Prick tests for house dust mite, pollen, animal dander, and food proved to be negative. Patch tests with the European Contact Dermatitis Group (ECDRG) standard series and textile color and finish series were negative. Histologic examination of the dermis showed a slight perivascular superficial inflammatory infiltrate composed of lymphocytes, neutrophils, and eosinophils, in association with dermal fibrosis. Immunohistochemistry (anti‐CD4 Dako, anti‐CD8 Dako, anti‐CD79 Dako, anti‐CD3 Dako) showed lymphocytes with a CD4+/CD8+ T phenotype. Direct immunofluorescence gave a negative result. Microscopic examination of the peripheral blood showed no microfilariae, and no ova or parasites were detected in the first stool specimen. The second stool specimen revealed the presence of ova of Hymenolepis nana. The patient was treated with 2 × 100 mg mebendazole (Vermox®) given orally for 3 days. This treatment aggravated the skin eruption and the pruritus became more intense ( Fig. 2). 2Jarisch–Herxheimer reaction after starting treatment with mebendazole: diffuse, pruritic, erythematous lesions on the trunk with areas of edema Two weeks later, the patient presented with skin manifestations with similar characteristics to the first eruption, but less severe. Pruritus was still present but was only mild. New parasitologic investigations still showed a few ova of Hymenolepis nana in one of two stool samples. The patient was treated with praziquantel in a single oral dose of 40 mg/kg which was repeated after 7 days. The cutaneous eruption gradually disappeared and the itching decreased and cleared more slowly. The eosinophils in the blood and the total serum IgE level dropped to normal limits, and parasitologic investigations were repeatedly negative. The patient has been symptom free for 8 months.