Study of the Incidence and Nature of “Very Subtle Epidermal Melasma” in Relation to Intense Pulsed Light Treatment

BACKGROUND Skin rejuvenation with intense pulsed light (IPL) is effective for clearing epidermal pigment disorders. Complications are mild and limited to epidermal burns caused by excessive settings. Some patients, however, experience IPL-induced melasma-like hyperpigmentation despite the appearance of normal skin. These patients seem to have very subtle epidermal melasma not visible to the naked eye. Ultraviolet photography has been useful in identifying these patients and preventing complications. OBJECTIVE The study investigated the incidence of very subtle melasma in patients using UV photography, and assessed this tool in identifying high-risk patients. SUBJECTS AND METHODS 223 Japanese women, 30–69 years old, participated in the study. Very subtle melasma invisible to the naked eye under normal light was diagnosed by UV photography by two physicians, and any relationship among the disease incidence, age, and regular sunscreen use was examined. RESULTS Sixty-three cases of very subtle melasma (28.3%) were identified among the 223 subjects, with a significantly lower incidence in sunscreen users. CONCLUSIONS Patients diagnosed with subtle epidermal melasma and treated with mild IPL parameters did not suffer induced secondary hyperpigmentaion. To help avoid complications after treatment, IPL users should be aware of the age and sunscreen-related incidence of this phenomenon in Asian patients.