Follicular psoriasis causing erythroderma in a child: A rare presentation
A 13-year-old boy presented with scaling and erythema of skin since six months and difficulty in closing the eyes completely since four months. His skin lesions started as dark, rough, horny papules over the knees and elbows, which became erythematous and scaly after a few months and gradually spread to involve the whole body. Small areas of skin (spared of erythema and scaling) with these horny papules were still visible over the shoulders and flanks at the time of admission []. The face showed tightening of skin, bilateral ectropion of lower eyelids, furrowing of skin of the nasolabial area, and fissuring at the angle of the mouth []. Scalp was covered with thick scales. Palmoplantar hyperkeratosis was present and associated with thick, lusterless nails with subungual hyperkeratosis, and longitudinal ridging [].\nThe joints of both the knees were widened with bilateral genu valgum []. The range of movement was normal, but they had recently become painful. Radiographic findings suggested changes similar to rickets. Family history was negative and there was no history of trauma, drugs, infections or any other triggers for his condition.\nBased on the above findings and after careful exclusion of other causes of erythroderma in children, a clinical diagnosis of erythroderma due to follicular psoriasis was made. This was confirmed by histopathology [] which showed parakeratosis, hypogranulosis, elongated rete ridges with corresponding dermal papillary hyperplasia, suprapapillary thinning of epidermis, and neutrophilic infiltrate in the dermis. The follicles also showed plugging and ostial parakeratosis.\nThe patient was managed conservatively using emollients and a well-controlled fluid and food intake. Methotrexate was started in the dose of 7.5 mg/week after ensuring that the routine investigations were normal. A single injection of vitamin D (6 lakhs IU) was given for the joint deformities and braces were advised for the same. The erythroderma showed significant improvement in 3 weeks and the follicular lesions resolved completely by 8 weeks.