A sun allergy or photosensitivity is an allergic reaction triggered by the immune system in certain individuals who experience a change in the skin which is affected by the sun causing their immune system to treat this skin as if it were something 'foreign' and tries to defend against it.
Researchers and scientists have not been able to determine why this relatively rare disorder happens in certain individuals and not others.
The symptoms typically include an itchy red rash which most commonly appears on the back of the hands, the outside areas of the arms, lower legs, and neck.
One of the most common types of sun allergy is 'PMLE' or 'Polymorphous Light Eruption' which has been reported as being the second most common cause of medical problems being related to the sun with the first being sunburn.
'PMLE' includes the typical red itchy rash and is seen in individuals of all races which usually appears for the first time in young adulthood and is typically seen more in women than men.
'Actinic Prurigo' or 'hereditary PMLE' is a form of 'PMLE' which is generally inherited and occurs in individuals of American Indian descent.
This form of 'PMLE' typically starts earlier in life during childhood or the adolescence stage.
'Photoallergic eruption' is another common cause of photosensitivity and is triggered by a chemical reaction from products which have been applied to the skin such as certain lotions, fragrances or sun screens, as well prescription medications which have been ingested such as commonly prescribed antibiotic, high blood pressure, and psychiatric medications.
Prevention is the best medicine when it comes to a sun allergy and sunscreens with a high 'SPF' should be used at all times while going out in the sun as well as a full awareness of any medications you may be taking that can have an adverse reaction to the sun.
Typically the symptoms of an allergic reaction to the sun go away in a few hours or may last up to a couple of days however, if you experience severe symptoms or other complications you should seek help from a medical professional as soon as possible.