For some people, being outdoors exposed to sunlight can cause their skin to react by forming an uncomfortable, red, itchy rash known as “sun poisoning” or “sun allergy.” Often occurring during the spring or early summer, this sun sensitivity (photosensitivity) is not the same thing as sunburn.

Usually the rash appears several hours after sun exposure and can last for a few days.  Occasionally, the skin may break out in hives within minutes of sun exposure.  This annoying unsightly skin condition can prevent a person from participating in outdoor activities limiting time spent with family and friends.

Causes of sun allergy

It is not completely understood why a person may develop sun sensitivity.  This is a condition that may run in families and the immune system appears to be one of the factors involved in its development.  The auto-immune disease of lupus and the rare, inherited metabolic disease of porphyria, are both known to cause sun sensitivity. 

In people with lupus, a butterfly rash appearing over the nose and cheeks along with discoid rashes that appear as disk-shaped, raised, scaly patches on any sun-exposed area of the body can be triggered by sun exposure. 

Rosacea can also cause a rash from sun exposure.  Medications can be another source of photosensitivity – tetracycline and other antibiotics, some antidepressants, and certain drugs taken for hypertension, high blood sugar, heart conditions, and acne – can also increase sun sensitivity. 

Other factors leading to a development of a sun allergy may include herbal supplements such as saw palmetto and St. John’s wort.  Even putting on fragrances, cosmetics, skin creams and some sunscreens, can be a culprit of sun sensitivity.

Treating sun allergy

The best tip is to avoid any prolonged sun exposure being especially careful at mid-day when ultraviolet light is strongest.  Be sure to apply sunscreen not forgetting to apply to areas on the back, neck and around the ears that may be exposed.  Wear protective clothing and a wide-brimmed hat.  If traveling to a sunnier climate or higher altitude, be particularly careful and take precautions. 

Often the rash will go away on its’ own and if a person gradually increases sun exposure during warmer months, they will become less sensitive.  Over-the-counter anti-inflammatory/anti-itch creams can help bring relief when a rash has occurred. 

If the rash is severe or getting worse, seek help from your doctor to determine the exact cause and to prescribe topical or oral medications.  Testing the skin with a photo-patch can reveal if a skin product is to blame.  Light therapy has been used to help desensitize the skin to the sun.