Involucrin in the differential diagnosis between linear psoriasis and\ninflammatory linear verrucous epidermal nevus: a report of one case
A 4-year-old girl presented with numerous confluent verrucous papules, either\nhypochromic or erythematous, linearly distributed, some along the Blaschko's lines, on\nthe trunk, upper and lower limbs, since birth (). No other skin lesions, or ungueal, scalp or mucosal lesions were detected.\nLesions were located initially in the back of the patient's right hand, with\ndissemination to the rest of trunk and limbs over the years. The lesions were pruritic.\nHer medical history suggested substantial reaction to food allergies. She had a twin\nsister without skin lesions and there was no family history of psoriasis or of any other\nskin disorder. Given the clinical aspect, the diagnostic hypotheses were ILVEN,\nichthyosis hystrix, linear psoriasis, incontinentia pigmenti and lichen striatus.\nHistopathologic examination revealed a psoriasiform dermatitis, consistent with the\nclinical hypothesis of ILVEN and linear psoriasis, and it was not possible to\ndifferentiate between the two (). Results\nof immunohistochemical staining for involucrin revealed that this protein expression was\nincreased in the orthokeratotic regions but deficient in the parakeratotic regions\n(). The patient received topical\ntreatment with keratolytics and steroids, as well as systemic treatment with\nantihistaminic drugs. The treatments resulted in moderated improvement of the lesions\nand pruritus.