Successful treatment of severe psoriatic arthritis with infliximab in an 11-year-old child suffering from linear psoriasis along lines of Blaschko

Conflicts of interest: none declared Sir, The case of an 11‐year‐old boy who suffered from severe psoriatic arthritis and concomitant linear psoriasis following the lines of Blaschko is presented. At 6 months of age skin lesions appeared for the first time and a clinical diagnosis of psoriasis was made, confirmed by a skin biopsy taken at the age of 6 years. Lesions appeared in a linear fashion following the lines of Blaschko. Mainly the left part of his body was affected; pits were present in most nails, as well as onychodystrophy at the left thumb and hallux. At the age of 3 years the patient was additionally diagnosed with psoriatic arthritis. The lesions persisted at the same sites with varying intensity, showing only partial and temporary response to treatment. Psoriatic arthritis developed into a highly inflammatory type with painful swollen joints requiring methotrexate 5–10 mg m−2 body surface weekly and later ciclosporin 3–4 mg kg−1 as higher doses of methotrexate could not be tolerated by the patient. Skin lesions were treated with topical calcipotriol and corticosteroids, but complete remission was never achieved.