Longer-wave laser found effective in treating certain KP symptoms

Results of a new study suggest that treatment of keratosis pilaris (KP) with a longer wavelength laser is effective for improving skin roughness and textural irregularities, but does little for the erythema associated with KP.

The Northwestern University study notes that KP often is resistant to treatment, and that shorter-wavelength lasers used to reduce the associated erythema fall short in smoothing out textural irregularities. The researchers set out to determine whether the longer-wavelength 810-nm diode laser would be more effective overall.

The team set up a randomized clinical trial at a dermatology outpatient practice from March 1 to October 1, 2011. The trial involved 23 patients diagnosed as having KP on both arms and Fitzpatrick skin types I through III. Eighteen of the patients completed the study, three were unavailable for follow-up, and two withdrew due to inflammatory hyperpigmentation following laser treatment.

Patients were randomized to get treatment with the 810-nm pulsed diode laser on either the right or left arm. Treatments were repeated twice for a total of three treatments administered four to five weeks apart.

Primary outcome measure was the difference in disease-severity score, including redness and roughness/bumpiness, with each graded on a scale of zero (least severe) to 3 (most severe) between the treated and control sites. Two blinded dermatologists rated the sites at 12 weeks after the first visit.

At follow-up, the blinded raters assigned a 2.0 median redness score for both the treatment and control sides. The median roughness/bumpiness score was a 1.0 for the treatment sides and a 2.0 for the control sides. The median overall score combining erythema and roughness/bumpiness was 3.0 for the treatment sides and 4.0 for the control sides.

“Three treatments with the 810-nm diode laser may induce significant improvements in skin texture and roughness/bumpiness in KP patients with Fitzpatrick skin types I through III, but baseline erythema is not improved,” the authors conclude. “Complete treatment of erythema and texture in KP may require diode laser treatment combined with other laser or medical modalities that address redness.”

Ibrahim O, Khan M, Bolotin D, et al. Treatment of Keratosis Pilaris With 810-nm Diode Laser: Randomized Clinical Trial. JAMA Dermatol. 2014: doi:10.1001/jamadermatol.2014.2211