Polymorphous light eruption is a skin condition in which a person develops a sensitivity to the sun’s UV rays (UVA light is the usual culprit). This sensitivity will often result in an itchy rash, consisting of small red bumps and raised patches of skin, similar to hives in appearance. Polymorphic light eruptions tend to affect people more in the spring and summer months, when a person’s exposure to sunlight is increased. The skin may harden to the sun as the summer progresses so they may not develop the condition in late summer. Typically more females than males are affected by this condition. Sun avoidance and protective measures such as the use of a broad spectrum sunscreen are effective in preventing the occurrence of rashes. In most cases, polymorphic light eruption rashes will resolve on their own without treatment. However, persistent and recurring cases may require procedures such as phototherapy. Always rule out systemic lupus as this can also cause photosensitive rashes.

Common symptoms of polymorphous light eruptions include:

  • A rash consisting of clusters of small red bumps
  • Itchiness
  • In some cases, swelling or blistering may occur

An acquired sensitivity to the sun’s UV rays is the primary cause of polymorphous light eruptions. Exposure to sunlight triggers an autoimmune reaction that produces an inflamed rash.

Be gentle when caring for skin that is sensitive or sun damaged. For example, use gentle cleansers that are fragrance and allergen free to avoid irritating damaged areas of the skin. Look for moisturizers that contain UV filters against UVA and UVB rays, which can offer additional safeguards against sun damage. Make sure to apply these frequently and generously, to adequately hydrate and protect the skin.

Since polymorphous light eruptions are caused by exposure to UV rays, it’s important to take preventive measures when going outdoors. In addition avoid any drugs that may cause photosensitivity.

Limit sun exposure: Reducing your time in the sun is perhaps the easiest way to avoid damage to your skin caused by UV rays. When outdoors, set a time limit and seek shade when necessary. Also keep in mind that UV radiation is the strongest between the hours of 10 a.m. to 4 p.m.

Use sunscreen: Sunscreens are an essential part of protection against the sun. Look for sunscreens that are labeled “Broad Spectrum”. They are often the most effective and offer protection against both UVA and UVB rays. Make sure to apply generously and frequently.

Cover and protect: Wrap-around sunglasses, wide-brimmed hats and clothing that covers your arms and legs, can offer extra protection against the sun’s harmful UV rays.

Look for any changes in your skin: If you notice changes in existing moles, or new skin growths, consult with a dermatologist immediately to determine if the symptoms may be precancerous.

Daily use of a sunscreen can help keep your skin protected from UV rays. Look for sunscreens that contain the following ingredients: Benzophenone, Oxybenzone, Avobenzone, Titanium Dioxide and Zinc Oxide. Make sure your sunscreen offers protection against both UVA and UVB rays. These will be simply labeled “broad spectrum”.Anti-itch creams containing hydrocortisone are recommended to treat symptoms of itching.

The use of Hydroquinone may help some patients if taken for a couple of weeks in the early spring. The use of topical steroids to suppress the rash is helpful.

Phototherapy is often recommended to treat seasonal cases of polymorphous light eruptions. In this procedure the skin is exposed to low amounts of UVA and UVB light, which helps the skin become less sensitive to sunlight.