After a long winter, it might be tempting to get some sunshine once the warmer weather begins. As we spend more time outdoors, it is important to protect against the strong summer rays. Sunlight contains harmful ultraviolet rays that increase the risk of skin cancer, accelerate aging of the skin, and flare connective tissue disease.
Sunlight that reaches the Earth’s surface contains two types of ultraviolet (UV) light, both A and B.
- UVB light is more damaging, causing sunburns and altering DNA in the body’s cells.
- Sunlight contains about 10-20 times more UVA light, which penetrates the skin more deeply.
Both forms of UV radiation cause skin cancer and premature aging of the skin. Tanning beds also produce UVA and UVB radiation, often at much higher levels than the sun.
Sun protection is especially important for people with connective tissue disease. Even for individuals with darker skin tones, sunlight can trigger disease.
- Lupus Erythematosus: Sunlight, both UVA and UVB, leads to a variety of symptoms ranging from skin rashes to internal organ damage, even weeks to months after exposure to the sun. UV light can trigger the butterfly rash of lupus and cause scarring in chronic lupus lesions of the skin.
- Dermatomyositis: Rashes in dermatomyositis arise in sun-exposed areas, such as the scalp, face, V-neck chest, and shoulders. These rashes can burn, sting, or itch.
- Scleroderma: Although certain types of UV light are used as a treatment to lessen skin thickening, some scleroderma patients are photosensitive and develop rashes or sunburns quickly. UV light can also worsen the hyperpigmentation (darkening) of scleroderma skin.
What drugs cause sun sensitivity?
It is important to recognize that many medications cause the skin to be more sensitive to light, also known as photosensitizing. This manifests as sunburn or rashes developing after brief exposure to UVA radiation.
Common photosensitizing drugs include:
- Antibiotics (eg. Bactrim, Cipro, Levaquin, Doxycycline and other tetracyclines)
- Antimalarials (eg. Plaquenil)
- Blood Pressure Medications (eg. Diltiazem/Nifedipine, Hydrochlorothiazine)
- Immunosuppressant drugs (eg. Imuran, Methotrexate)
Some immunosuppressant medications, such as azathioprine and cyclosporine, used to treat connective tissue disease may also increase the risk of skin cancer. These medications impair the immune system to repair or destroy UV-damaged cells, allowing mutated DNA to develop into skin cancer.
How can I protect myself from the sun?
- Avoid the sun between 10 a.m. and 2 p.m. At these times, a greater amount of UVB reaches the Earth. Eating lunch indoors can be a smart idea.
- Remember that, even on cloudy days, we still are exposed to about 80% of the ultraviolet light present on a sunny day. Recreational activities near water require additional caution as water reflects up to 80% of the sun’s rays.
- Wear protective clothing, such as a wide-brimmed hat and long sleeve shirts. Tightly woven or dark fabric offers the best protection. Some companies specialize in high-UPF (Ultraviolet Protection Factor) clothing, hats, and umbrellas.
- Physical Protectors: window glass blocks UVB light, however, UVA can still penetrate. Since UVA can worsen lupus and dermatomyositis, light penetrating through windows can flare disease. Protective window films applied to car windows or windowpanes can offer additional protection.
- Use broad-spectrum sunscreen with an SPF of 30 or higher.
What types of sunscreen are available?
Sunscreens are made of a mix of ingredients that reflect or absorb light, preventing damaging UV rays from penetrating the skin.
Overall, sunscreens are divided into physical or chemical blockers.
- Physical blockers reflect ultraviolet light away from the skin. Examples are zinc oxide and titanium dioxide.
- Chemical blockers absorb and turn ultraviolet light into energy that cannot damage the skin. There are many types, including oxybenzone, avobenzone, ecamsule.
It is important to pick a sunscreen that offers protection from both UVB and UVA rays. These sunscreens are called “broad spectrum”.
What is SPF?
SPF stands for sunburn protection factor and is a scientific way to measure how much a specific sunscreen protects the skin from sunburn due to UVB compared to skin that is unprotected. SPF does not measure how much a sunscreen protects from UVA light.
How should I apply sunscreen?
- When to apply: 15-30 minutes before sun exposure to allow the sunscreen to bind to your skin.
- How much to apply: The average adult will need one ounce (about a palm full or one shot glass) of sunscreen to cover all skin exposed to sun.
- How often to re-apply: Every two hours, or immediately after swimming or sweating too much. Some sunscreens offer “water resistance” for 40 or 80 minutes. This means the skin can be wet or sweaty for 40 or 80 minutes prior to needing to apply again.
Don’t forget your lips and eyes and select lip balms that are broad spectrum and contain at least SPF 30.
Select sunglasses that offer 99% protection from UVA and UVB and remember, the wider the sunglasses, the more area they protect.
Are tanning beds dangerous?
It is a dangerous myth that UV rays only damage skin after a sunburn. Even the development of tanned skin is evidence that UV light is changing cellular activity in the skin and causing DNA damage. Tanning beds not only cause a very high increase in skin cancer and melanoma, but also can cause life-threatening disease in patients with connective tissue disease.
Cosmetic bronzers and sunless tanners can safely give the appearance of a tan. This “tan” does not provide any protection from UV-light, so sun protective measures should still be used.
Isabela Wieczorek, MD
Department of Dermatology, Weill Cornell Medical College
Horatio F. Wildman, MD
Department of Dermatology, Weill Cornell Medical College