Published: February 2010
Publications
Summer reminder - photosensitivity reactions
Prescriber Update 31(1): 7-8
February 2010
Now that summer is here healthcare professionals are reminded of the risk of photosensitivity reactions with a number of topical and systemic medicines.
CARM adverse reaction data shows that the ten most commonly reported medicines associated with photosensitivity reactions in New Zealand are:
- Doxycycline
- Hydrochlorothiazide
- Amiodarone
- Piroxicam
- Chlorpromazine
- Trimethoprim/sulfamethoxazole (Co-trimoxazole)
- Captopril
- Enalapril
- Bendroflumethiazide
- Carbamazepine
Photosensitivity reactions typically appear as unexpected sunburn or a dry or blistering rash on sun-exposed skin, which may or may not be itchy. The most commonly affected areas are the face, neck, arms, backs of hands, and often lower legs and feet. The reaction may occur immediately or as long as 72 hours after exposure to ultraviolet (UV) light.
The New Zealand Dermatological Society recommends that patients take the following precautions when using a medicine which has been associated with photosensitivity reactions:
- Cover up with closely-woven clothing.
- Wear a broad-brimmed hat.
- Avoid direct sunlight whenever possible. Ultraviolet rays, sunlamps, and sunbeds should also be avoided. Try to keep in the shade or carry an umbrella.
- Apply a good broad-spectrum sunscreen liberally to all uncovered skin before exposure. Sunscreen should be applied at least 30 minutes before sun exposure and re-applied every two hours, as well as after swimming or exercise.
- Insect repellents reduce the sunscreen's sun protection factor (SPF) so when using together, use a sunscreen with a higher SPF and re-apply more often.
If patients experience a photosensitivity reaction, the main goal in the treatment is to identify the photosensitising agent and withdraw it if possible. In cases where the medicine cannot be withdrawn patients should be advised to follow the sun protection strategies listed above.
Further information can be found on the New Zealand Dermatological Society
website:
http://dermnetnz.org/reactions/drug-photosensitivity.html
