Acne Light Therapy

Light based therapies for acne target deeper layers of the skin and do not harm the skin’s surface. Some light therapies target the P.acnes bacteria, while others destroy the sebaceous glands. Acne light therapy can improve the skin’s texture. Hence it is considered a good therapy for both active acne and acne scars. 

Photodynamic therapy (PDT) is gaining in popularity as an effective treatment for acne. The therapy involves activating a photosensitizing agent (drug) by exposing it to a red, blue or pulsed light source. Hence, it uses a combination of light and topical medications. These light sources are visible non-laser or invisible laser lights. It is this procedure of combining a drug with light, which gave this acne treatment the name ‘photodynamic therapy’. 

A non-laser, high intensity, visible narrow band of blue light is used in targeting the P.acnes bacteria, which causes inflammatory acne. P.acnes inhabits the sebaceous glands producing porphyrins – a chemical by-product of the metabolism of these bacteria. Visible blue light hones in on the porphyrins and activates it therefore causing the death of the bacterial cells. The sebaceous glands are now expected to slow down in their production of sebum, therefore reducing the incidence of inflammatory acne outbreaks.

Photodynamic therapy / PDT Process

Acne light therapy has to be performed by a trained technician, nurse or doctor. They will apply aminolevulinic acid (ALA) to the skin. This is a clear, painless, strong photosensitizing agent. It increases the skin’s sensitivity to light. ALA is left for 15-60 minutes on the skin. During this time, it accumulates in the target cells of the sebaceous glands. Now an intense blue ray of light activates ALA. This process takes about 8-10 minutes. A chemical reaction then takes place that creates heat and kills the bacteria.

Other light therapies

  • Blue light therapy exposes the skin to low-intensity blue light that destroys P.acnes. it is a painless procedure and requires ongoing treatment for the P.acnes bacteria keep resurfacing.
  • Heat energy and pulsed light therapy combines both these sources to shrink sebaceous glands and destroy P.acnes bacteria.
  • Diode laser therapy destroys sebaceous glands in the dermis. This therapy can be painful and painkillers will be administered before treatment.
  • Photopneumatic therapy uses a vacuum suction to remove dead skin cells and oil from the sebaceous glands. The infected area is then treated using red and blue light to kill P.acnes bacteria. 

Advantages of light therapies

Acne light therapy is often effective where other therapies have failed. It is especially beneficial in treating hard-to-reach areas like the shoulders and back. It also helps in curing acne scars.  It works very well as part of an overall acne treatment plan. Patients experience the best benefits when they undergo several sessions. Following proper skin care regime after treatment can achieve good results.

acne light therapy Side effects and Limitations of light therapies

Side effects of light therapies for acne

Light therapies have some side effects too. While they are not very common but a patient who undergoes PDT can experience swelling of the areas that were treated, pigment changes, crusting and dryness. Patients could experience other side effects of PDT such as telangeictasia (prominent blood vessels), skin discoloration, swelling of the eyes, blisters, reaction to the topical medication etc. 

The side effects produced by all the other light therapies are similar – redness, swelling and dryness of the treated areas.

Limitations of light therapies for acne

Key limitation is that the results of acne light therapies are unpredictable. Not everyone will experience similar results – some may benefit more and others less. Acne may not clear 100% with light therapies. E.g. A person who undergoes blue light therapy may experience 30%-60% clearing after several sittings. Results of all light therapies are temporary and medications are required to prevent a recurrence of acne. The treatment is expensive and insurance usually does not cover the cost. All light therapies produce some side effects that can last from a few hours to a few days.

Precautions after light therapies for acne

There are certain precautions that must be observed after PDT. If you expose yourself to sun immediately after treatment, you can develop severe sunburn and skin peeling. Hence, for two days after this treatment, you must not expose your body to strong, direct light. If you need to go out, use adequate sun protection.

The duration of avoiding harsh lights depends on the quantity of drug used and the dosage. If the drug was administered intravenously then your skin and eyes could be sensitive to light up to 6 weeks after treatment. If you used topical medication, then sensitivity will last only for 2-3 days. Only the areas where the drug was applied will be sensitive. 

Your dermatologist will suggest other precautions you can follow once you undergo acne light therapy. First do not scrub the area with harsh soaps or face scrubs, do not pick or poke the area if it is irritating. Use only non-irritating sunscreens and moisturizers; wash the area often after treatment using mild soap and water; use OTC antibiotic ointments to reduce swelling and redness; avoid using cosmetics on freshly treated areas and finally, applying ice packs to the treated areas can be soothing.

Dermatologists could also recommend that patients sleep on a reclining chair or with pillows propped up on the bed. This is beneficial in reducing swelling when treatment was done on the head and face. Always inform your doctor about all medications you are taking and any infections you have like colds before undergoing light therapies. If you experience adverse reactions especially increase in swelling or fever return to your doctor at once. 


Acne light therapy is considered to be effective by many but to achieve overall satisfactory results, this therapy may need to be used along with other treatments as well. This is because photodynamic therapy targets only P.acnes and not other causes of acne. Since this form of destruction of P.acnes bacteria is temporary, it could resurface rapidly and start attacking your skin again. Hence, combining treatments is the best way to achieve long term results in controlling acne outbreaks. 

Always consult a certified dermatologist before undergoing any acne light therapy.