Background: Post-inflammatory hyperpigmentation (PIH) after laser treatment of Hori nevus remains problematic. Prevention and treatment of PIH have limited success.

Objective: To study the effects on hyperpigmentation using topical antibiotic alone versus combined antibiotic and betamethasone/valerate after 1064 nm Q-switched Nd:YAG laser treatment of Hori nevus.

Method: Twenty-five cases of Hori nevus treated with Q-switched Nd:YAG laser randomly applied topical fucidic acid (control group) or fucidic acid plus betamethasone/valerate (study group) on assigned cheek immediately post laser for 2 weeks. Pigmentation was measured using the mexameter as melanin index (MI) and erythema index (EI), at baseline, 2nd and 4th weeks. Photographic evaluation and patient global assessment were done at the 4th week.

Results: Twenty-three cases completed the study. No patient developed side effect from either creams. The comparison of M and E-indexes of the control versus the study group revealed no significant difference. However, there was a uniform increase of M index of the control group compared to the study group.

Conclusion: Applying topical corticosteroid immediately after laser treatment decreased pigmentation. Although not statistically significant, there was a tendency for lightening. Future studies are needed with more patients, duration of follow-ups and histological studies to assess pigmentary changes.