We receive a lot of questions on our skin sites about skin reactions to sunlight. For some people, especially women, just a little exposure to the sun can cause rashes, hives and other skin irritation. When someone has this type of skin reaction to the sun we say that they are photosensitive. There can be many causes for photosensitivity including medications and skin diseases such as psoriasis and rosacea. Yet there are two other skin conditions which cause photosensitivity that you may not know about. One of the common factors of these skin conditions is that they primarily affect women. In this post we are going to tell you about Polymorphous Light Eruption (PLE) and Solar Urticaria.
To help us learn more about these photosensitivity-specific disorders we are calling upon the expertise of our consulting dermatologist, Dr. Lawrence Green, a practicing dermatologist and Assistant Clinical Professor of Dermatology at the George Washington University School of Medicine.
To find out more about Dr. Green please visit his website: Aesthetics, Skin Care, and Dermasurgery.
Question: Can you tell us about polymormphous light eruption and the signs and symptoms that one may have this condition?
Dr. Green: Polymormphous light eruption (PMLE) is thought to be an autoimmune disease (like diabetes, lupus, and psoriasis) where the skin's immune system is making a mistake and reacting to ultraviolet rays from the sun. PMLE is more likely to occur in places where the sun is stronger (like at higher altitudes or climates closer to the equator). Someone can have PMLE and be exposed to the sun in Canada, but not have problems until they travel to a place like Florida. Typically, PMLE appears as a red, blotchy non-scaly rash in sun exposed sights a few days after exposure. The rash can itch, and lasts until a few days after you have stopped going outside in the sun.
Question: What is solar urticaria and how does it manifest?
Dr. Green: Solar urticaria is a form of hives-although it is also probably has an autoimmune trigger. Like PMLE, solar urticaria is trigger by ultraviolet light from the sun. Unlike PMLE, solar urticaria presents as welts of hives appearing n the skin within minutes to an hour after the sun exposure. Once you leave the sun, solar urticaria goes away much more quickly than PMLE, usually within a matter of hours.
Question: What is the treatment for these two conditions?
Dr. Green: The mainstay of treatment for both conditions is avoiding the sun in locations that stimulate the rash, or wearing protective clothing when outside. Broad spectrum sunscreens (like those that contain the ingredient zinc oxide) are the best way to protect areas you can't cover with clothes. But, even sometimes these sunscreens are ineffective. To my knowledge, people who have PMLE or solar urticaria are not more likely to get skin cancer than anyone else, but these people really have to avoid sun exposure or protect themselves or their rash will always recur.
Additional Facts about PLE and solar uticaria:
- Both PLE and solar urticaria can be chronic conditions lasting for years.
- PLE is a relatively common skin condition affecting 10-15% of people in North America.
- Solar uticaria is considered to be a rare skin condition caused by an allergic reaction to the sun.
- In addition to a stinging itchy rash some people with solar uticaria may feel light-headed, nauseated and have a headache.
- Cold compresses may help alleviate symptoms of both conditions as well as applying hydrocortisone cream. In more severe cases your dermatologist may prescribe a stronger steroid cream or ointment. Antihistamines may help decrease the symptoms of solar uticaria.
- Some people who are extremely sensitive to the sun can also experience symptoms of their solar uticaria or PLE even in the winter.
For more information about potential causes and treatments for photosensitivity please refer to the following Health Central articles and resources: