Topical psoralen (methoxsalen) (valid on areas close to the equator only)

Your doctor has just prescribed a topical methoxsalen paint for you. It is also called meladinine.

What is topical methoxsalen used for?

Methoxsalen belongs to a group of medicines called psoralens. Topical methoxsalen is used on the skin to treat vitiligo or other skin problems as determined by your doctor. It increases the sensitivity of the treated areas of your skin to high intensity long wave ultra violet light (UVA). This treatment is called PUVA.

This medicine has been prescribed for your current skin condition only and should not be given to other people or used for other problems.

How should I use topical methoxsalen?

• Topical methoxsalen comes in the form of a lotion or paint. Use on the affected depigmented areas of skin as directed by your doctor. Treatment usually starts with 2 applications a week.
• Before each application, wash, clean and pat dry the affected areas. Apply a sunblock with SPF 15 or above, to the surrounding areas of normal skin that will be exposed to the light.
• Paint the depigmented areas with methoxsalen paint and allow to dry.
• Expose these areas to light for the duration of time as determined by your doctor. You will normally be directed to start with short exposure times of 0.5 – 1 minute and increase it by 0.5 minute every treatment until the treated areas become pink.
• You should shine at the same time everyday.
• Note this exposure time and maintain it for subsequent treatments. Do not increase the exposure time any longer or a serious burn may result.
• Wash the paint off thoroughly with soap under a running tap immediately after each light treatment.
• Cover the treated areas with a sunblock with SPF 15 or above at all times during the day. Continue to do so until about a week after your doctor stops your PUVA treatment.
• The treatment works best if exposure to ultra violet light takes place immediately after you apply the paint on the skin. Treatment may not be as effective if exposure is delayed after application.

What should I do if I forget an application?

If you miss any application, skip the dose and resume your usual schedule. Do not increase the number of applications or spend more time in the sunlight. This may result in a serious burn.

What other effects can topical methoxsalen cause?

• Dry or itchy skin. You may apply any emollient or moisturizer, for example, aqueous cream, emulsifying ointment, liquid paraffin, olive oil, urea cream or vaseline.
• Long term PUVA treatment increases the risk of developing skin cancer. Check your body regularly and report to your doctor about any skin sores that do not heal, new skin growths or existing skin growths that have changed in the way they look or feel.
• Prolonged PUVA treatment may also cause permanent premature ageing of the skin. This is similar to skin ageing caused by excessive sunbathing.
• Inform your doctor immediately if any of these effects occur.

Contributors:

Dr Christophe HSU – dermatologist. Geneva, Switzerland

National Skin Centre. Singapore