Non-ablative fractional photothermolysis in treatment of idiopathic guttate hypomelanosis.

BACKGROUND: Idiopathic guttate hypomelanosis (IGH) is a common pigmentary disorder affecting a large number of individuals. Many patients seek medical attention due to aesthetic concern. However, no standard treatment is available.

OBJECTIVES: To evaluate the efficacy and side-effects of non-ablative fractional photothermolysis (FP) as a treatment of IGH.

MATERIALS AND METHODS: A total of 120 lesions from 30 patients with IGH were treated. In each patient, two lesions on the extremities were assigned to treatment group, while lesions from the other side served as control. The treatment was delivered by fractional 1550-nm ytterbium/erbium fibre laser for four times at 4-week intervals. Lesional skin colour was measured by colourimetry. Digital photographs and dermoscopic digital photographs were taken at weeks 0, 4, 8, 12 and 16. In addition, patient satisfaction score and side-effects were recorded. All clinical photographs were evaluated by three experienced dermatologists to determine clinical improvement using a quartile grading scale.

RESULTS: Colourimetry of the treatment side showed normalization of skin colour at each visit and was statistically significant when compared with control after two treatments (week 8) and continued to decrease until 4 weeks' follow-up (week 16) (P = 0.047, 0.016 and 0.06 respectively). Physicians' improvement grading score showed that 83.34% of the lesions in treatment group vs. 18.34% in the control group showed some improvement. The difference was statistically significant (P < 0.05). Common side-effects were erythema and oedema in treatment area, which were mild and transient. No post-inflammatory hyperpigmentation was observed.

CONCLUSION: Non-ablative FP appears to be an effective way to treat IGH. The improvements are documented by both objective and subjective measurements.