LAUSR

A 16-month-old Caucasian boy presented with an 8month history of chronic intensely pruritic crops of pustules affecting the scalp, face and limbs. The pustules occurred intermittently in crops and were aggravated by childhood viral illnesses. Both medication and family history were unremarkable. He had been tried on numerous courses of oral antibiotics and topical steroids of varying potencies, with little benefit noted. Physical examination revealed multiple excoriated and dried pustules on the scalp (Fig. 1a) and some peripheral pustules on the legs (Fig. 1b), with less well-defined lesions on the arms, torso and face. There was no lymphadenopathy or mucosal involvement. There was no evidence or family history of scabies infection. Routine haematological investigations revealed normal haemoglobin level, low mean corpuscular volume (72 fL; normal range 80–96 fL) and peripheral eosinophilia (1.67 9 10/L; 0.04– 0.4 9 10/L). Biochemical parameters including liver function tests, renal function and bone profiles were normal. He had low levels of ferritin (7.3 lg/L; 15– 300 lg/L) and total iron (8.3 lmol/L; 12–30 lmol/L). Screening results for coeliac disease, human immunodeficiency virus, other viruses, immunoglobulin and glucose-6-phosphate dehydrogenase deficiency were normal, while screening for varicella zoster virus infection was positive. Chest radiography gave normal results, while results for skin swabs taken for bacteriology and virology, and fungal skin scrapings were unremarkable. Histopathological findings