Generalized keratosis pilaris rubra mimicking erythromelanosis follicularis faciei et colli: a case report

Introduction and Importance: Keratosis pilaris rubra (KPR) is a benign follicular disorder characterized by erythematous papules and perifollicular inflammation, typically affecting adolescents and young adults. The generalized form is rare and diagnostically challenging due to overlap with erythromelanosis follicularis faciei et colli (EFFC). Case Presentation: A 19-year-old obese Buddhist male presented with longstanding erythema and rough, bumpy papules over the cheeks, neck, trunk, and all four extremities, associated with burning sensations. Dermoscopy showed follicular keratotic plugs, perifollicular erythema, a diffuse reddish background, and multiple linear vessels. Histopathology of a cheek biopsy demonstrated follicular infundibular plugging with perifollicular lymphocytic infiltrate, supporting KPR. Topical tretinoin 0.05%, mometasone 0.1% cream, urea-based moisturizer, and sunscreen led to mild improvement in texture, with persistent erythema. Clinical Discussion: Generalized KPR is uncommon and can be mistaken for EFFC owing to overlapping clinical and dermoscopic features. Dermoscopy (follicular plugs, perifollicular erythema, linear vessels) and histology (infundibular plugging, perifollicular lymphocytes) help distinguish KPR, while EFFC typically shows pigmentary changes and dermoscopic peppering. Therapeutic options beyond topical agents include pulsed dye laser and topical sirolimus in selected cases. Conclusion: This case underscores the diagnostic complexity of generalized KPR and the importance of correlating clinical, dermoscopic, and histopathological findings. Conventional therapies provide limited benefit, and financial constraints may restrict access to advanced options like laser treatment.