Certolizumab pegol induced paradoxical psoriatic alopecia with therapeutic response to bimekizumab

Certolizumab pegol nduced paradoxical psoriatic alopecia with therapeutic response to bimekizumab Dear Editor,The increasing prevalence of immune-mediated diseases has led to widespread use of biologics such as TNF- inhibitors. 1 A known complication of these agents is Paradoxical Adverse Reactions (PARs), often manifesting as new-onset or worsened psoriasis.Clinically and histologically, these lesions typically mimic conventional psoriasis.Improvement upon drug discontinuation and worsening with continued therapy are characteristic. 2We present a rare case of paradoxical psoriatic alopecia associated with certolizumab pegol, successfully managed with bimekizumab.A 29-year-old woman with ankylosing spondylitis, treated with certolizumab pegol for 1.5-years, presented with sudden-onset scalp hair loss and erythematous, scaly plaques.There was no mucosal, nail, or other cutaneous involvement, and she had no personal or family history of dermatologic disease.Laboratory findings were within normal limits.A punch biopsy from a scalp plaque revealed parakeratotic crusting with nuclear debris, superficial hemorrhage in the stratum corneum, focal acanthosis, and loss of the granular layer, along with mild spongiosis, interface vacuolar degeneration, and dyskeratosis (Fig. 1A---B), while PAS staining was negative.This clinicopathologic constellation was consistent with TNF- inhibitor ---related paradoxical psoriatic alopecia.Certolizumab was discontinued, and bimekizumab was initiated.During follow-up, partial hair regrowth with reduced scaling of the alopecic plaque was noted at week-4.By week-8, further regrowth and near-complete resolution were observed.At the 6month follow-up, complete resolution of the scalp scaling and restoration of normal skin texture were achieved, with near-complete hair regrowth except for mild residual thinning along the midline (Fig. 2A---C).