Phototherapies including LED light therapy and photodynamic therapy (PDT) are commonly used and considered safe treatment for inflammatory acne. However, there are few reports about the combination of the two methods on the same patient. We report a rare case of blue light induced transient localized acne post PDT. A 32-year-old male with a history of moderate to severe acne for 3 years was successfully treated by 3 sessions of modified red light 5-aminolevulinic acid (ALA) PDT without adverse events during the PDT treatment. However, when he received blue and red LED light therapy as maintenance one week post the last ALA-PDT, severe localized acne burst on his nose. Subsequently, he received single red light treatment for a month, combined with oral administration of doxycycline for the first week. His severe acne on the nose was recovered eventually. No recurrence was observed later.

Photodynamic therapy

Blue light

Adverse event

Acne

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