Topical 5-aminolevulinic acid photodynamic therapy improved refractory acne conglobata and perifolliculitis capitis abscedens et suffodiens rather than hidradenitis suppurativa

Acne conglobata (AC), perifolliculitis capitis abscedens et suffodiens (PCAS) and hidradenitis suppurativa (HS) are uncommon refractory chronic, inflammatory, scarring diseases but cause serious damage to the quality of life. These three diseases are associated with follicular occlusion. Several studies indicated topical 5-aminolevulinic acid photodynamic therapy (ALA-PDT) improved follicular occlusion besides acne treatment. So we attempted to apply ALA-PDT to medicine resistant AC, PCAS and HS. Topical ALA-PDT was applied to 10 patients with AC, seven patients with PCAS and three patients with HS for more than three sessions. All the patients completed the dermatology life quality index (DLQI) questionnaire and were assessed for the efficacy at the baseline and on two weeks after each treatment. Adverse effects were recorded at each visit. The results showed 25.5% (5/20, two cases of AC and three cases of PCAS) of patients achieved excellent improvement after three sessions of PDT and another 60.0% (12/20, eight cases of AC and four cases of PCAS) of patients achieved good improvement. 15.0% (3/20, three cases of HS) got poor response (< 20% lesions clearance). Another five cases (three cases of AC and two cases of PCAS) also achieved excellent response after 5–7 sessions of PDT. We also found that papular/nodular, cyst/abscess showed higher clearance rate than sinus/fistula (88.5%, 86.1% versus 11.1%). DLQI was reduced after three sessions of PDT in AC and PCAS patients rather than HS patients. 5-ALA-PDT could improve refractory AC and PCAS but could not lead to improvement in late stage of HS. The efficacy increased with more treatment sessions