The Skin, Sunlight and Lupus

LEARNING ABOUT LUPUS: A USER FRIENDLY GUIDEFrom the Lupus Foundation of Delaware Valley, Inc.Edited by: Mary E. Moore, Ph.D., M.D., Carolyn H. McGrory, MS, RN, Robert S. Rosenthal, M.D.

The Skin, Sunlight and Lupus
Warren R. Heymann, MD

Sensitivity to the sun from exposure to ultraviolet light (either sunlight or artificial sources) is one of the symptoms the American College of Rheumatology uses to diagnose systemic lupus erythematosus. This chapter will review the effects of lupus on the skin and will explore what is known about the relationship between ultraviolet light and lupus. it will also discuss what the lupus patient should do to avoid the damaging effects of the sun.

The cause of lupus is unknown. Many factors may be involved in the clinical picture of lupus in a particular individual. Exposure to sunlight may play an important role either in the start of lupus in some patients or in causing flares of existing disease in others. It is important to realize that many lupus patients are not negatively affected by the sun. For this reason lupus has been called a "photoaggravated" disorder or one which may be, but is not always, made worse by the sun. Lupus represents a wide range of disease. At the less severe end of the range is discoid (chronic cutaneous) lupus.

Generally, patients with discoid lupus have few problems which affect the whole body. Most patients with discoid lupus have skin problems on the head, scalp, and neck. First these appear as red, swollen plaques (a raised circular patch of skin) while later the patients experience thinning of the skin, scarring, changes in skin color and "plugging" of the hair follicles.

Aggravation of discoid lupus by the sun is quite variable but may occur in up to 50% of patients. The more severe form of lupus is systemic lupus erythematosus. Symptoms affecting the skin are the "butterfly" rash on the nose and cheeks, hives, a net-like pattern of redness on the arms and legs ("livedo reticularis"), dilated blood vessels of the finger and toe nail folds ("periungual telangiectasias"), hair loss and ulcers of the lining (mucous membrane) of the mouth, nose, or the vagina. Sun sensitivity may occur in lupus after even mild sun exposure.

It is also possible to find sun sensitivity in a less severe form of lupus called subacute cutaneous lupus. The skin findings in this condition may resemble psoriasis or have a ring-like (annular) shape. These lesions are found in areas exposed to sunlight (i.e.. face. upper chest, upper back, and sides of the arms). Systemic findings are mild and are usually limited to joint and muscle pains. it should be emphasized that because lupus involves a range of symptoms, an individual may have any of the skin or systemic features.

Although it is evident that lupus may be negatively affected by ultraviolet radiation, little is known about how this actually occurs, Most experts agree that ultraviolet B radiation, the "sunburn" rays, (290-320 nm) are most important. There is some evidence, however, that ultraviolet A radiation, the "tanning" rays, (320-400 nm) may also result in sun sensitivity reactions. The theory behind this is that ultraviolet light may alter the DNA (deoxyribonucleic acid) of the uppermost layer of the skin (epidermal cells) so that DNA causes an immune response. DNA is the material of which genes are made. DNA which is not exposed to the sun's rays does not cause this immune response, while sun-exposed DNA does.

It is also possible that sunburn may act as a non-specific trauma or injury. Other environmental agents such as cold, heat, and wind may also aggravate lupus or cause it to begin in a previously well person. Individuals affected by lupus should learn to protect their skin from the sun. By practicing common sense measures, the sun need not be strictly avoided and the out-of-doors may be enjoyed. The midday sun should be avoided (between 11 A.M. and 2 P.M.). Use of a broad-rimmed hat or staying in the shade is encouraged, and the use of sunscreens should become a daily habit. A sunscreen with a sun protection factor (SPF) of at least 15 is recommended for the summer months.

Remember that snow reflects sunlight and if the individual likes to be outside throughout the year, use of sunscreens should be continued in all seasons. Tanning parlors are absolutely taboo for the lupus patient. It is apparent that ultraviolet rays may affect all forms of lupus, especially systemic lupus erythematosus. Although it is not understood exactly how this occurs, it is clear that by fairly simple precautions the damaging effects of sunlight on patients with lupus may be diminished or avoided altogether.


=========================================================== This information is for "informational purposes" and is not meant to be used for medical diagnosis. Always consult your physician on matters such as this.