Successful treatment with secukinumab of psoriasis‐like dermatitis in a patient with holocarboxylase synthetase deficiency

Abstract Holocarboxylase synthetase deficiency (HSD) is a rare autosomal recessive disorder of biotin metabolism. Typical manifestations include irreversible metabolic disorders and erythroderma‐like dermatitis. Most patients respond well to biotin supplementation. Psoriasis‐like phenotype associated with this disease has been rarely reported in the literature and experiences with the use of biologics in patients with HSD are still lacking. We reported a rare case of recurrent psoriasis‐like skin lesions in a 6‐year‐old child with HSD. The patient did not respond to initial therapy with high‐dose oral biotin. Immunofluorescence staining showed an increased number of interleukin (IL)‐17A+ cells in his skin lesions. Based on this finding, the patient was successfully treated with human anti‐IL‐17A monoclonal antibody (secukinumab). He did not report any side effects and remained healthy during the 2‐year follow‐up. We provide a comprehensive review of the reported cases of HSD with psoriasis‐like dermatitis to date. The psoriasis‐like phenotype of HSD is controversial in treatment and IL‐17A inhibitor is an alternative therapeutic option.