Photodynamic therapy is an effective and convenient treatment for solar keratoses and some skin cancers. It leads to less scarring than many other treatments, but it sometimes causes significant discomfort and irritation of the skin, which can be managed both in the clinic and at home after the procedure.

What to expect following treatment

In most cases, there is only mild discomfort following treatment, but some people experience stinging and pain which can be bad enough to disrupt sleep and interfere with normal activities. This usually lasts 12-24 hours.

Swelling and redness may persist for about a week. There may be raw areas which weep - this is usually a normal part of wound healing and does not necessarily mean that the skin is infected. Don't treat weeping skin with antiseptics such as Dettol or Betadine. These antiseptics can be toxic to the cells involved in the wound healing process. If you think your skin is infected, contact your doctor as soon as possible.

The aminolevulinic acid cream used during treatment is activated by light. The skin may be very sensitive to sunlight for several days following treatment.

As the skin heals, it may peel or develop crusts. The peeling and crusts are sometimes unsightly and may affect your ability to work or go out for a while.

Pain relief

Pain after PDT can often be managed with cold compresses (e.g. an ice pack or cool, wet towel).

If oral painkillers are required, take paracetamol 4 to 6-hourly. If we suspect you will experience an especially strong or painful reaction to treatment, we'll prescribe strong painkillers.

Do not take anti-inflammatory medications such as ibuprofen, naproxen or diclofenac. The treatment relies on inflammation and these medications might reduce its effect.

Applying petroleum ointment such as Vaseline, Bepanthen, Infadolan or petroleum-based paw paw ointment to the treated area can also provide relief.

Sun exposure

Avoid sun exposure on the treated areas for 3-4 days following treatment.

If you are outside, cover the treated area with clothing or a dressing if possible. Use a non-stick dressing such as Melolin. If your face was treated, wear a broad-brimmed hat.

Crusted and peeling skin

As the skin recovers, about 2-3 days after treatment you may notice peeling and crusts developing. Do not pick at the scabs or peel the skin off.

In some cases, there is a very strong reaction to treatment. This usually means that there is significant underlying sun damage to the skin.

In such a reaction, you might experience:

  • pain, redness and swelling for 2-3 days
  • small fluid-filled blisters or pustules (Note: this pus is not necessarily a sign that the skin is infected; it's a known reaction to the inflammation caused by PDT. However, if you have a fever or if any of the pustules are especially tender to touch, this may be a sign of infection and you should contact us soon as possible.)
  • peeling of the top layer of skin
  • development of a crust over the treated area
  • itch of the treated area (This is a sign of healing.)

The reaction sometimes takes 2-3 weeks to settle and there may be residual redness of the treated area for 2-3 weeks after this.

Unfortunately, we can't always predict who is going to experience this type of strong reaction to treatment. It's more likely if there is extensive sun damage to the treated area (e.g. many solar keratoses or a history of multiple skin cancers in the affected area).

If you experience a very strong or uncomfortable reaction to photodynamic therapy, please don't hesitate to contact us for advice.


Our doctor or nurse will call in the days following your treatment to check on your progress, answer your questions and recommend treatments for pain and inflammation if required.

In most cases, your doctor will want to see you again for a follow-up appointment to see how well the treatment has worked. This will normally be in about 1 month.

PDT is effective 80-90 per cent of the time, which means that you may require a further treatment, or possibly treatment alternatives such as surgery.