Photodermatitis is an abnormal skin reaction to sunlight, or more specifically to ultraviolet (UV) rays. It can be acute (sudden) or chronic (ongoing). Photodermatitis occurs when your immune system reacts to UV rays. You may develop a rash, blisters, or scaly patches. Exposure levels and reactions differ for every person.
Several factors can make your skin sensitive to UV rays, including having an inherited tendency to photosensitivity, taking certain medications, or being exposed to plants in the Apiaceal or Umbelliferae family, including weeds and edible plants, such as hogweed, cowbane, carrot, parsnip, dill, fennel, celery, and anise.
Signs of photodermatitis include:
Photodermatitis can have several causes, including:
In reaction to UV rays, certain chemicals and drugs can cause sunburn, an eczema-like reaction, or hives. The reaction may be related to an allergy, or it may be a direct toxic effect from the substance. Below are examples of substances or circumstances that may trigger one or the other type of reaction:
Direct toxic effect:
People who are most at risk include:
Your health care provider will perform a physical exam and take a detailed history of your exposure to chemicals, drugs (see What Causes It? section), and UV rays. Your provider may order blood and urine tests to detect any related diseases. Allergy tests may help identify substances that may trigger or worsen the condition.
These measures may help prevent photodermatitis:
For blisters or weepy eruptions, apply cool, wet dressings. With certain types of photodermatitis, doctors may use phototherapy (controlled exposure to light for treatment purposes) to desensitize the skin or to help control symptoms.
For extremely sun sensitive people, doctors may prescribe azathioprine to suppress the immune system. Short-term use of glucocorticoids may help control eruptions. For those who cannot be treated with phototherapy, doctors may prescribe hydroxychloroquine, thalidomide, beta-carotene, or nicotinamide (see Nutrition section).
Note: Thalidomide causes severe birth defects and should never be used by women who are pregnant or wish to become pregnant.
If you do not get enough of some nutrients, your skin can become sensitive to sunlight. Pellagra, for example, is caused by a niacin deficiency and leads to photosensitivity. Other nutrients, particularly antioxidants and flavonoids, may help protect skin against sun damage in healthy people. Antioxidants help protect skin from damage. Recent studies suggest that antioxidants, especially beta-carotene, may help lessen the symptoms of photodermatitis.
Some supplements and herbs may be beneficial for some people but cause side effects or undesired drug interactions in others. Always tell your health care providers about any supplement or complementary therapy you are using or considering using.
You may address nutritional deficiencies with the following supplements:
Herbs are generally available as standardized, dried extracts (pills, capsules, or tablets), teas, or tinctures/liquid extracts (alcohol extraction, unless otherwise noted). Mix liquid extracts with favorite beverage. Dose for teas is 1 to 2 heaping teaspoonfuls/cup water steeped for 10 to 15 minutes (roots need longer).
Herbs to avoid
Some herbs can cause photodermatitis, including:
Few studies have examined the effectiveness of specific homeopathic remedies. A professional homeopath, however, may recommend one or more of the following treatments for photodermatitis based on his or her knowledge and clinical experience. Before prescribing a remedy, homeopaths take into account a person's constitutional type, includes your physical, emotional, and intellectual makeup. An experienced homeopath assesses all of these factors when determining the most appropriate remedy for a particular individual.
Most photosensitivity reactions go away eventually and cause no permanent harm. However, symptoms can be serious when there is an underlying disease or when the exposure has been severe. Some photosensitivity reactions can continue for years after exposure ends.
Complications may include:
People who need steroids to treat photodermatitis must be monitored closely. In addition, anyone with a history of photodermatitis or photoreactivity should keep track of the frequency and duration of symptoms. This information can help determine appropriate treatment.
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Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.
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