By George J. Hruza, MD

Xu LY et al. Histopathologic study of hidradenitis suppurativa following long-pulsed 1064-nmNd:YAG laser treatment.
Arch Dermatol 2010Sep 20; [e-pub ahead of print]. (http://dx.doi.org/10.1001/archdermatol.2010.245)

Aggressive treatment with hair removal laser such as Nd:YAG 1064 nm may have a positive effect on lesions of HS. Hidradenitis suppurativa (HS) is very resistant to both medical and surgical management — exacerbations, recurrence, and progression are the norm.

See hidradenitis suppurativa pictures

The observation that HS (aka Acne Inversa) may be related to follicular occlusion has led to attempts to treat HS with hair removal lasers. In this prospective, controlled clinical and histologic study,20 patients with Hurley stage II HS (skintype, Fitzpatrick III or VI) underwent treatment with a long-pulsed 1064-nm Nd:YAG laser.

The patients received two treatments to one affected area; untreated affected areas served as controls. The patients were followed clinically, with biopsy specimens obtained before treatment and at 24 hours,1 week, 1 month, and 2 months after treatment. Laser parameters were adjusted based on skin type and ranged from 25 to 50 J/cm2, with a 10-mm spot size and a 20- to 35-millisecond pulse duration. Double pulse stacking was used at the first treatment, and triple pulse stacking at the second treatment on inflammatory lesions.

As measured by a Lesion Area and Severity Index score modified for HS, patients realized a statistically significant improvement of 32% in treated areas 2 months after the second treatment. No significant adverse events were reported.

Baseline and 24-hour biopsy specimens showed perifollicular inflammation, a superficial and deepmixed infiltrate, and granulation. At 1 week, inflammation and granulation had increased. By 1 month, inflammation had decreased and broken hair shafts were noted. At 2 months, the investigators found scarring, fibrosis, and minimal inflammation. These conditions correlated with the degree of clinical improvement. Patients with the greatest clinical response had the least inflammation.

Laser hair removal seems to achieve modest improvement in hidradenitis suppurativa by destroying the offending hair follicles. To be effective, the treatments need to be quite aggressive, as evidenced by the stacked pulses used in the study and the histologic evidence of scarring and fibrosis. Multiple treatments with a hair removal laser will probably be needed to achieve significant reduction in disease activity. The duration of remission is yet to be determined.