Dupilumab's Successful Journey in Pityriasis Lichenoides Chronica Followed by the Intriguing Reemergence of Vitiligo after Monobenzone Depigmentation: A Case Report.

INTRODUCTION: Pityriasis lichenoides (PL) is an inflammatory skin disorder encompassing both acute (PLEVA) and chronic (PLC) subtypes, which share overlapping clinical and histopathological features. Standard treatment modalities include oral antibiotics, phototherapy, and immunosuppressive agents. Dupilumab, an IL-4Rα antagonist approved for atopic dermatitis, has been used off-label for various inflammatory skin conditions. However, its role in PLC management remains poorly documented.

CASE PRESENTATION: We report a case of PLC successfully treated with dupilumab. The patient had a history of vitiligo and had previously undergone monobenzone depigmentation therapy. Due to concerns regarding potential pigmentary changes, dupilumab was initiated with a loading dose of 600 mg, followed by 300 mg biweekly. After 3 months of therapy, there was significant improvement in PLC lesions and pruritus, with only residual erythematous plaques. Unexpectedly, spontaneous skin repigmentation occurred, contrasting with previous reports of vitiligo exacerbation following dupilumab use. The patient resumed monobenzone therapy without experiencing PLC recurrence or worsening pruritus.

CONCLUSION: This case highlights dupilumab's potential as an effective treatment for PLC and its possible role in promoting skin repigmentation in a patient with prior vitiligo. These findings suggest a potential link between type 2 inflammation and PLC pathogenesis, warranting further investigation. Dupilumab may represent a promising therapeutic alternative for refractory PLC.