In patients with hidradenitis suppurativa (HS), microwave ablation via the miraDry® (Miramar Labs Incorporated, Santa Clara, California) device has no apparent clinical benefit and may even be harmful in individuals with mild disease, according to the results of a randomized controlled intrapatient trial ( Identifier: NCT03238469) conducted in The Netherlands and published in the Journal of the American Academy of Dermatology.

The investigators sought to evaluate the efficacy and safety of the microwave ablation device for the treatment of patients with mild axillary HS. Overall, 9 patients with HS were randomly allocated to a single miraDry treatment (5.8 GHz, energy level 5, manufacturer’s recommended settings) in 1 axilla while receiving tumescent anesthesia. A total abscess and nodule (AN) count between 3 and 5 per axilla was required for eligible patients, with no more than 1 abscess or draining sinus.

The primary study outcome was a left-to-right comparison of the axillary area via use of the Hidradenitis Suppurativa Clinical Response (HiSCR). Secondary outcomes were a numerical rating scale (NRS) regarding pain per axilla, treatment satisfaction, and hair follicle count.

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Negative clinical outcomes experienced during the recruitment period prompted the researchers to conduct an interim analysis, which resulted in discontinuation of the study. Of the 9 patients undergoing treatment, 1 did not tolerate the treatment due to extreme pain while undergoing the procedure despite receiving local anesthetics.

Eight patients completed the miraDry treatment, all of whom were women, with a median age of 31.5 years (range, 28.0 to 39.0 years). Among these 8 patients, 7 completed the 3-month follow-up, with 1 patient discontinuing because of worsening HS symptoms in the axilla treated with the microwave ablation technique. Moreover, 2 patients attained HiSCR in the miraDry-treated axilla vs 2 patients in the comparator axilla (P =1.00). Further, 5 of 8 patients exhibited worsening of their disease following miraDry therapy, with an increase in AN and sinus counts.

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Patients experienced active lesions during a median of 43.0 days (range, 4.0 to 90.0 days) in the miraDry-treated axilla vs a median of 5.5 days (range, 2.0 to 26.0 days) in the contralateral axilla (P =.14). After 3 months, the median NRS score for pain in the miraDry-treated axilla was 7.0 (range, 2.0 to 8.0) vs 0 (range, 0 to 5.0) in the untreated axilla (P =.07).

The number of hair follicles after 3 months was numerically lower in the miraDry-treated axilla, with a median of 4.0 cm-2 (-50.9% from baseline) vs a median of 8.5 cm-2 (-2.0% from baseline) in the untreated axilla.

The investigators concluded that because the microwave ablation technique targets a dermal zone rather than a particular structure, its nonselectivity may have resulted in the poor study outcomes reported herein.


Vossen ARJV, van Huijkelom MAPC, Nijsten TEC, et al. Aggravation of mild axillary hidradenitis suppurativa by microwave ablation: results of a randomized intra-patient controlled trial [published online June 22, 2018]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2018.06.032.