Topical PDT highly effective for primary axillary hyperhidrosis
Grapevine, Texas — Photodynamic therapy (PDT) using a topically applied liposomal eosin hydrogel is an effective treatment for primary axillary hyperhidrosis, according to a study reported at the 31st annual meeting of the American Society for Laser Medicine and Surgery.
The procedure was developed by Abeer Attia, Ph.D., and colleagues at the National Institute of Laser Enhanced Sciences, Cairo University. It involves one hour of incubation with the photosensitizer and photoactivation using an intense pulsed light (IPL) device.
Its efficacy was demonstrated in a split-side, controlled, patient-blinded trial enrolling 20 adults who underwent four treatments at weekly intervals with the eosin gel applied to the right axilla and placebo gel to the left. Patients had a minimum six-month history of primary axillary hyperhidrosis with an age of onset less than 25 years and relatively symmetric sweating on both sides and had to report at least one excessive sweating episode impairing daily activities weekly. They also had to have a positive Minor's starch-iodine test.
"Based on the results of our study, we believe PDT using a topical eosin hydrogel and IPL may offer new hope to patients suffering from primary axillary hyperhidrosis," Dr. Attia says.
The treatment was well tolerated, and at one week after the last session, the PDT-treated axillae showed a statistically significant, 90 percent reduction from baseline in the area of sweating (65 cm2 at baseline to 5.7 cm2) that was also significantly greater than the 2.2 percent change recorded on control side.
Efficacy was also seen in analyses of subjective data, including symptom rating using the Hyperhidrosis Disease Severity Scale (HDSS) and patient satisfaction, and the treatment benefit was maintained in all patients during follow-up extending to eight months, says Dr. Attia, assistant professor of dermatology.
The HDSS data showed that all patients were considered to have had severe hyperhidrosis at study entry, with 15 patients (75 percent) having an HDSS score of 4 and the rest having a score of 3. At one week after the last treatment, the HDSS score improved from baseline in all patients, with seven patients (35 percent) reporting a three-point improvement, nine (45 percent) achieving a two-point improvement, and the other four (25 percent) benefiting with a one-point improvement. Only three patients reported an improvement on the control side at the last follow-up, and it was only one point in magnitude. Notably, onset of efficacy was also relatively rapid, Dr. Attia says.
"HDSS scores were unchanged at one week after the first PDT session, but at one week after the second treatment, 19 patients reported a one-point improvement at the treated site and the remaining patient had a two-point improvement," he says. "At the same visit, three patients reported a one-point HDSS improvement on the placebo-treated side, but with worsening thereafter."
Dr. Attia also observed that the symptomatic improvements exceeded that which would be predicted by the mean reduction in sweating area considering data presented by Kowalski et al, who reported that a one-point improvement in HDSS score corresponds with a 50 percent reduction in sweat production and a two-point improvement corresponds to an 80 percent reduction (Kowalski JW, Eadie N, Dagget S, et al. J Am Acad Dermatol. 2004;50(3 suppl):p51). "Some patients in our study who still had a positive starch-iodine test reported being completely free of symptoms. Ultimately, however, the patient's perception of the benefit may be the best metric for determining efficacy," Dr. Attia says.
Eosin is a fluorescent red dye approved by the Food and Drug Administration for use in lipsticks, and its formulation in liposomes results in a hydrophobic product that enhances penetration of the active ingredient to its target, i.e., the sweat glands in the deeper dermis.
Based on studies showing eosin had an optimum absorption peak at 517 nm, the IPL device was equipped with a 400 nm filter to select for longer wavelengths. The irradiation was performed using a fluence of 25 J/cm2 and pulse duration of 20 ms. "Compared with use of a laser, an IPL device allows for illumination of a larger area of skin, and with our chosen settings, the total irradiation time per axilla was only three minutes," Dr. Attia says.
Manal Salah, M.D., Maha Fadel, Ph.D., and Shahira Almenshawy, Ph.D., collaborated with Dr. Attia in the development and evaluation of the topical PDT. Results of the study have been published (Salah M, Attia A. J Egypt Womens Dermatol Soc. 2011;8(1):36-42).
Disclosures: Liposomal eosin hydrogel was prepared and supplied as a gift by the pharmaceutical technology lab, National Institute of Laser Enhanced Sciences, Cairo University. Dr. Attia and colleagues report no relevant financial interests.