Many light therapy patients don’t realize that what they eat or the medicines they take can affect their sensitivity to UV light. Those treating with light therapy should educate themselves on these photosensitizers before they receive phototherapy treatments and help prevent themselves from seeing red.

A photosensitizer is a substance that creates sensitivity to light when absorbed by the cells. This can be in many forms; namely drugs, lotions, oils and foods.

What does this mean to those using phototherapy treatment for psoriasis, vitiligo, or other skin issues? It means they must use care to avoid becoming over-sensitive to light which can interfere with their phototherapy regimen.

Some photosensitizers are well known and easy to avoid.  However, there is a lengthy list of common foods and essential oils that may surprise you.  It is also surprising to know that simply handling certain foods may cause sensitization of the hands – even if the food is not ingested!

These photosensitizers and others could cause erythema following your phototherapy treatment so help yourself stay informed with the list below:

Citrus fruits can be strong photosensitizers:

  • Bergamot
  • Bitter orange (cold pressed)
  • Grapefruit (cold pressed)
  • Lemon (cold pressed as well as distilled)
  • Lemon verbena
  • Lime (cold pressed as well as distilled)
  • Mandarin
  • Orange
  • Tangerine (cold pressed)
  • Yuzu

Other foods, herbs, essential oils and supplements can have a similar photosensitizing effect:

  • Angelica root
  • Carrots
  • Cassia
  • Celery
  • Coriander
  • Cumin
  • Dill
  • Fennel
  • Fig
  • Ginger
  • Mustard
  • Parsley
  • Rue
  • Tagetes
  • Verbena

For a complete list of photosensitizing substances, including drugs and medications, Click Here to visit the FDA’s website.

So, if your phototherapy patient suddenly gets erythema following a treatment, their light therapy regimen might not be to blame!  Check their diet and routine to see if a photosensitizer could be the culprit.