Refractory Seborrheic Dermatitis Treated With a 532-nm Q-Switched Potassium Titanyl Phosphate (KTP) Laser: A Case Report.

Seborrheic dermatitis (SD) is a common, chronic inflammatory skin disorder that can be challenging to manage when refractory to conventional topical therapies. This case report describes the use of a 532-nm Potassium Titanyl Phosphate (KTP) Q-switched laser in a patient with refractory SD. A 25-year-old male patient presented with persistent erythematous, scaly, and pruritic facial lesions. Clinical evaluation included histopathological confirmation and Seborrheic Dermatitis Area and Severity Index (SEDASI) scoring, with an initial score of 46 points. The patient underwent four sessions of 532-nm KTP Q-switched laser treatment (8 J/cm², 10-ns pulse duration, 3-mm spot size, 5 Hz frequency, three non-overlapping passes per session), in combination with standard topical therapy (ketoconazole 2% shampoo and ceramide-based sunscreen). Following the fourth session, the SEDASI score decreased from 46 to 23 points, corresponding to a reduction from "very severe" to "moderate" disease severity. This was accompanied by clinical improvement in erythema, scaling, and pruritus. A three-month follow-up demonstrated sustained improvement without recurrence. No adverse effects were observed apart from transient erythema. Immediate whitening noted during treatment was consistent with a possible photomechanical effect. In this single case, 532-nm KTP Q-switched laser therapy was well tolerated and associated with clinical improvement. Given the inherent limitations of a case report, these findings should be interpreted with caution. Further controlled studies are required to better define the safety, efficacy, and potential role of this modality in refractory SD.