Blue light therapy is a noninvasive treatment for acne that uses light to kill certain bacteria on the skin.

A form of phototherapy, blue light treatments are FDA-approved for acne vulgaris that is moderate or has not responded to other therapies.

Blue light therapy can be carried out in a dermatologist’s office or at home.

Fast facts on blue light therapy:

  • Blue light therapy uses light in the blue wavelength range to kill the bacteria Propionibacterium acnes, or P. acnes, on the skin.

  • There is no recovery time, and the treatment has relatively few, if any, adverse effects.

  • Studies show moderate evidence for the efficacy of blue light treatments for people with mild to moderate acne.

  • It should be noted that most studies on blue light therapy are small and do not report on long-term results. There is a lack of data for outcomes in cases of severe acne.


Phototherapy is the use of ultraviolet light, which is found in sunlight, for the treatment of skin disease. Although natural sunlight is sometimes used for certain diseases, artificially produced ultraviolet light is generally used as it is easily controlled, is available and is convenient and less time consuming for patients. The phototherapy equipment available in the department has capability of producing UVB and UVA. UVB is short wavelength UV that is often used in the hospital to treat psoriasis. UVA is longer wavelength UV used with the drug psoralen in the treatment referred to as PUVA and is generally used in an outpatient setting. In addition, narrow band UVB is now available.

Phototherapy is most frequently used to manage psoriasis. It is also helpful in the treatment of a multitude of other skin problems, including: cutaneous T-cell lymphoma, vitiligo, lichen planus, granuloma annulare, pityriasis rosea, acne, generalized itching from various causes, diseases of the hands and feet, atopic and other types of eczema.