Medications and Sun Sensitivity

by: Léa Riegelhaupt MPharm, Pharmacist

Sunshine, strawberries and much longer days; this can only mean one thing: summer is back!

Summer means more exposure to the sun, either in Britain or in more exotic parts of the world and therefore, we thought it might be useful to remind you that using adequate sun protection is necessary, especially for people using medicines  for IBD.

Just a quick reminder: the sun emits several kinds of waves, two of which are UVA and UVB waves. Exposure to UV radiation makes the skin produce more melanin which makes the skin darker and therefore less sensitive to the sun. In other words, we get a tan.

Those waves also have other properties: they are responsible for positive effects like the production of vitamin D by the skin, but they also cause unwanted effects like skin and cell damage.

People who are medically treated for IBD should take particular care in the sun because several of the medicines can cause photosensitivity. Photosensitivity is an exceptionally high sensitivity to the UV waves in sunlight. In the short term, this means severe sunburns, peeling skin and sometimes also a (blistering) rash. In the long term, exposure to the sun whilst taking medicines which cause photosensitivity can lead to increased risks of skin cancer.

Medicines used in IBD known for causing photosensitive effects are:

Sulfasalazine (Salazopyrin®)
Azathioprine (Imuran®)
Mercaptopurine (Puri-Nethol®)

However, if you’re taking any of these medicines, there’s no need to panic.

By adopting a few simple reflexes, you can reduce your risks of short and long-term photosensitive reactions.

  1. Always use sunscreen before sun exposure. Sunscreen protects your skin against both UVa and UVb radiation. The protection against UVb is indicated by the Sun Protection Factor (SPF). Make sure you always use sunscreen of at least SPF 15 and ideally higher (SPF 30 or 50). UVa protection is measured with a star rating going from 0 to 5 stars where 5 stars is the maximum protection.
  2. Sunscreens also have a limited shelf life, usually about 2 or 3 years. Check the expiry date or the number of months it can be used for after first opening.
  3. Apply sunscreen about 30 minutes before sun exposure and remember to reapply it every couple of hours.
  4. Also reapply sunscreen after swimming, even if it’s a waterproof one.
  5. Try to stay out of the sun between 11 am and 3 pm, cover up and use an umbrella.
  6. Avoid using sunbeds or sunlamps.

Medicines that are supressing the immune system could always diminish the skin’s defence mechanisms against skin cancers. Therefore, even if the medicine you’re taking is not listed as causing photosensitive effects (e.g. steroids, Remicade®, Humira®), it’s always recommended to stay safe and protect yourself against the sun.

One last piece of advice: keep in mind that using sunscreen doesn’t mean you can stay in the sun as much as you want, it’s just a protection when exposure to the sun is unavoidable.

If you have questions or require more information, your pharmacist or GP can help you.

Have a great summer!



About the author

Léa Riegelhaupt MPharm

Léa Riegelhaupt MPharm

Léa is a community pharmacist who’s been working for the past two years in different pharmacies across London.

She moved from Belgium to London after graduating as a pharmacist at the University of Antwerp.

By working as a pharmacist and also on a personal level, she’s been involved with many IBD patients and has a deep understanding of the symptoms of Crohn’s Disease and Ulcerative Colitis and the way they affect the quality of life of the patients, the medication used to treat IBD and their possible side effects.


The Crohn's and Colitis Charity


New Report


Skip to toolbar