Vaccine-induced erythrodermic psoriasis in a child successfully treated with secukinumab: A case report and brief literature review.

We report a case of a 7-year-old male patient with vaccine-induced erythrodermic psoriasis (EP) complicated by pulmonary infection, hypoproteinemia, and liver dysfunction successfully treated with secukinumab in combination with symptomatic and supportive therapy. The patient presented with diffuse flushing on the head, face, trunk, and limbs, which were covered with chaff-like white scales in the rash-affected area, with no blisters, pustules, and no apparent abnormalities in the palms, soles, nails, and joints. Histopathology analysis revealed hyperkeratosis, focal parakeratosis, thinning or effacement of the granular layer, psoriasiform hyperplasia of the epidermis, neutrophilic microabscess formation in the upper part of the epidermis, edema of the dermal papilla, dilation of blood vessels, and lymphocyte infiltration. The patient was eventually diagnosed with EP. At weeks 0, 1, and 2, the patient received a subcutaneous injection of 150 mg secukinumab (three injections). Fluticasone propionate ointment, taccathitol ointment, yellow vaseline, and other drugs were also given topically. Following 2 weeks of treatment, the child's skin lesions resolved significantly with only slight pigmentation remaining and the Psoriasis Area and Severity Index (PASI) score decreased from 37.5 to 7.5 (PASI 75). Thereafter, 150 mg secukinumab was injected every 4 weeks until the last dose at 18 weeks (four more injections). After 18 weeks, the child's lesion resolved entirely (PASI 100), and no adverse effects were reported.