What is PDT?

Photodynamic therapy (PDT) is a treatment that uses light and a medicine (in a cream) applied to the skin to kill pre-cancer and early cancer cells. The treatment cream, known as ALA, is applied to the treatment area and left on the skin for up to three hours to be absorbed. Cancerous or pre-cancerous cells absorb significantly more ALA than normal cells. Once the skin has absorbed ALA, the treatment area is irradiated. The light source is the Omnilux LED Light. The light emitted activates ALA to causes a photo-toxic reaction which kills cancer cells.

What is PDT used to treat?

–          Precancerous skin changes, called Actinic keratosis, caused by years of sun exposure.

–          Diffuse actinic squamous dysplasia. This term describes skin with a lot of sun damage and often a history of skin cancer.

–          Bowen’s disease / squamous carcinoma in situ. This is early skin cancer.

–          Superficial Basal cell carcinoma. A skin cancer confined to the upper layers of the skin

Is the treatment painful?

When the light is shone onto the skin, the treatment area may begin to hurt. The severity of the pain depends on your skin’s reaction to the treatment. The treated area may initially become pink and puffy and may begin to ooze a little. After completion of PDT, discomfort and itching may last for a few days, and may require pain-killers.

What are the short-term side effects of PDT?

Your skin will be very sensitive to sun light after the PDT treatment, and you should avoid direct contact with the sun at all costs for at least 36 hours. You will experience scaling and crusting on the skin for at least one week, sometimes longer depending on your skin’s reaction. The treated area may also begin to blister or ulcerate. Occasionally, you will experience redness and swelling for up to four weeks post treatment. Your skin may also look lighter or darker.

Are there any long-term side effects of PDT?

There may be some scarring, and the skin may be left darker or paler after PDT. There is also the possibility that the treatment may not be effective in removing the condition. View a photographic sequence of the treatment here.


All patients having a PDT treatment are required to have read and signed the PDT document and are requested to bring it with on the day of treatment.   Download the Photodynamic Therapy (PDT) document here.

If you think you need a PDT treatment, we ask that you see your doctor first. PDT patients will only be booked and treated if they have a Doctor’s referral letter. You can email your referral letter to info@dermaclinic.co.za.