The largest organ you have is your skin. And if you let it sunburn, you may risk increasing your viral load-more so at lower CD4 counts. That’s the theory of longtime AIDS researcher Marcus Conant, professor of dermatology at the University of California at San Francisco. Lab research has found that mice burned by ultraviolet light experience immune suppression. In people, ultraviolet light is known to activate HIV, and other immunosuppressive influences have been shown to increase viral load. As viral-load counts become more common, Conant suggests, data may accumulate to test this theory. Meanwhile, sun exposure has other well-established dangers, which prudent avoidance and the right sunscreen can often prevent.

According to the FDA, people with HIV are especially susceptible to photosensitivity-severe burning and pain-when exposed to bright light. Tanning booths are as much a problem as the sun, the FDA says. In 1994, the Archives of Dermatology warned that with apparently health patients who have photosensitivity of unknown origin, HIV infection should be suspected.

Many drugs can cause photosensitivity. The most common offenders with PWAs include Bactrim or Septra, any sulfa- or tetracycline-based antibiotic or tricyclic antidepressant. Other problematic drugs: Ambien, Benadryl, Cipro, Compazine, Dapsone, Elavil, nonsteroidal anti-inflammatory drugs (NSAIDs) such as Motrin, Advil and Nuprin, oral contraceptives, Zithromax and Zoloft. Nondrug culprits can include the herbal extract hypericin, perfumes, some colognes and skin infections.

Wearing the right sunscreen may help protect you from photosensitivity reactions, but always check with your physician before you head for the beach. Ditto if you're considering solving the problem by taking a drug holiday-a potentially dangerous move that (depending on the drug) might spur the development of drug-resistant organisms.

The time of greatest sun damage is generally 10 am to 3 pm, so it's best to avoid midday sun altogether. But if you can't, use a sunscreen with a sun protection factor (SPF) of 30 to 45 and wear protective clothing (including a hat). An SPF of 15 is the absolute minimum PWAs should use at all times of sun exposure, with much higher levels at the beach or any place with bright light. Follow label instructions on how often to reapply.

UVA (a type of ultraviolet radiation) causes most drug-related reactions and skin damage such as aging and cancer. UVB (a second kind of radiation) is the major cause of sunburn. Most sunscreens offer protection from both; check the label to make sure. To protect against water and sweat for up to 80 minutes, buy a waterproof (not water-resistant or sweat-resistant) bran and apply it before you go out and again as needed. Conant says he has yet to see sunscreens give people with HIV any problems.

If for whatever reason you get sunburned, there are remedies. Blisters? See a doctor. Simple redness and mild pain? Try aspirin, drink water (not caffeinated or alcoholic beverages) and take potassium to help bring back your pep (orange juice and bananas are good sources). The most effective skin salve, according to many nutritionists, is vitamin E-just break open a capsule and spread it on the affected area. Aloe vera gel and calendula (herb-based) ointment can also be helpful. Or try applying plain yogurt (then rinse it off), a water and cornstarch mixture or undiluted apple cider vinegar. Useful compresses (applied for 20 minutes, three to four times daily) include cooled chamomile tea and witch hazel (use sterile cotton). How about adding baking soda to a tepid bath? Let it dry on you.

Better yet, you can prevent the problem altogether with the right "lube" and give your largest organ some tender loving care.