Novel ALA-PDT combined with intracavitary triamcinolone acetonide lavage for managing refractory PCAS.

Achieved significant symptom relief and hair regrowth in all four clinical cases.

Improved tolerability with minimal adverse effects compared to injection-based therapies.

Synergistic anti-inflammatory and photodynamic effects facilitate cystic cavity healing.

Provides a localized, minimally invasive alternative to systemic or surgical treatments.

Perifolliculitis capitis abscedens et suffodiens (PCAS) is a chronic, refractory, and recurrent inflammatory disorder of the scalp that severely affects patients’ quality of life and appearance. Despite various available treatments, no optimal therapeutic strategy has been established. Compared to conventional therapies, 5-aminolevulinic acid photodynamic therapy (ALA-PDT) demonstrates favorable efficacy and tolerability. Pretreatment before photodynamic therapy plays a crucial role in optimizing therapeutic outcomes. This study evaluated the efficacy of ALA-PDT combined with intracavitary triamcinolone lavage in the management of PCAS.

Four patients with PCAS were treated using ALA-PDT following intracavitary triamcinolone lavage pretreatment. Therapeutic efficacy was assessed by comparing symptom improvement before and after treatment.

All four patients achieved significant clinical improvement and exhibited good treatment tolerance, with no serious adverse reactions observed. During a minimum follow-up period of 6 months, no disease recurrence was detected in any of the patients.

ALA-PDT combined with intracavitary triamcinolone lavage pretreatment appears to be a safe and effective therapeutic option for PCAS. This combined approach may offer enhanced clinical outcomes compared with monotherapy, although treatment parameters should be individualized according to each patient’s condition.

Perifolliculitis capitis abscedens et suffodiens

Dissecting cellulitis of the scalp

ALA-PDT

Intracavitary triamcinolone lavage

Photodynamic Therapy

© 2026 The Authors. Published by Elsevier B.V.