Apremilast Associated Clinical Improvement in Bullous Pemphigoid With Plaque Psoriasis

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Figure S1: Clinical and histopathological findings. (a–c) Right forearm (a, b) and thigh (c) at the presentation. Scaly and indurated erythematous plaques are present, with several erosions overlying these plaques. Partial healing was observed following topical glucocorticoid therapy at the previous clinic. (d, e) Histopathology of an erythematous plaque, showing parakeratosis, loss of the granular layer, elongation of rete ridges, and a dermal lymphocytic infiltrate with scattered eosinophils (hematoxylin and eosin staining, original magnification ×40 in d, ×200 in e). (f) Thigh at week 36. The erythematous papules/plaques seen before apremilast initiation have resolved. Figure S2: Phosphodiesterase-4 immunostaining (original magnification ×100). (a) No phosphodiesterase-4 positive cells are observed in the present case. (b) Positive control from another patient with plaque psoriasis, showing phosphodiesterase-4 staining in the epidermis and infiltration of phosphodiesterase-4 positive cells in the dermis. Figure S3: Longitudinal changes after apremilast initiation. (a) Serum anti-BP180 NC16A IgG antibody titer (U/mL) and Bullous Pemphigoid Disease Area Index (BPDAI) plotted against time after apremilast initiation (weeks); both declined rapidly. (b) Serum total IgE (U/mL) decreased steadily over the same period. (c,d) Serum thymus and activation-regulated chemokine (pg/mL) and eotaxin-1 (pg/mL), and peripheral eosinophil count (/μL) remained largely unchanged. The dashed horizontal line in (d) marks 500 /μL (upper reference threshold). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.