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Delayed response of naevus of Ota to Nd‐YAG laser patch test

We wish to report on a delayed response to a test patch with the Nd-YAG laser for treatment of naevus of Ota on the face. This lesion is commonly found in patients with an Asian or Afro-Caribbean background. A 32-year-old Caucasian woman was referred to the laser treatment centre with a naevus of Ota on the right side of her face. She routinely used cosmetic camouflage to cover the mark but wanted to explore the possibility of laser treatment. We carried out a test patch (Figure 1) with an Nd-YAG laser (Candela Corporation) at 3.02 J using a 3-mm head at 532 nm. On review 3 months later we found no discernible lightening; hence, no further treatment was offered and the patient was discharged. However, the patient returned almost a year later with complete clearing of the mark in the treated area (Figure 2). Full treatment was then offered to the patient with good effect (Figure 3). This case is unusual in that response to treatment is generally seen within a few weeks after treatment. Although we have no explanation for this phenomenon, it is worth bearing in mind for patients who do not show a response within the accepted period of time.