Dermatomyositis (DM) is a rare autoimmune disease that affects the skin and muscles, often causing a distinctive rash and muscle weakness. While managing symptoms and medications is a major part of living with DM, one critical but often underestimated factor is sun exposure. For people with dermatomyositis, ultraviolet (UV) radiation from the sun can significantly worsen symptoms and trigger disease flares.
Dermatologist Dr. Victoria Werth, a leading dermatomyositis researcher at the University of Pennsylvania and a member of TMA’s Medical Advisory Board, emphasizes that photosensitivity is a key feature of DM, especially in those with skin-only forms like amyopathic dermatomyositis. “Even minimal sun exposure can lead to significant skin inflammation and disease flares,” she notes.
Here’s why UV exposure is particularly harmful for DM patients:
- Photosensitivity: The immune system in those with DM reacts abnormally to UV light, leading to inflammation and worsening of skin lesions.
- Flare-ups: UV exposure can trigger systemic flares, not just skin symptoms, potentially worsening muscle weakness and fatigue.
- Delayed Healing: The skin in DM patients is often fragile and slow to heal, making sunburns more dangerous.
- Increased Cancer Risk: Chronic inflammation and immune dysregulation may increase the risk of skin cancers, especially in sun-exposed areas.
Sun protection is not optional for those who live with dermatomyositis—it’s essential.
— Dr. Victoria Werth, dermatologist
How to Protect Yourself from UV Exposure
- Cover up with UPF (Ultraviolet Protection Factor) 50+ clothing.
- Opt for long-sleeved shirts, long pants, and wide-brimmed hats.
- Wear sunscreen with 70+ SPF rating every day, even under clothing; choose one with zinc oxide or titanium dioxide to block sun.
- Apply sunscreen even on cool or cloudy days and when driving.
- Reapply sunscreen every 2 hours
- Use UV-blocking umbrellas or canopies when outdoors. But be aware that you still need protection—60% of the sun’s rays reflect off sand and water.
- Enjoy the outdoors before 10am and after 4pm when the sun is not as strong.
- Avoid tanning beds and UV lamps such as those used in nail salons.
- Be aware that some indoor lighting (e.g., halogen or fluorescent bulbs) can emit low levels of UV radiation.
- Check the daily UV index using weather apps or websites, and avoid outdoor exposure when the index is 6 or higher.
Living with dermatomyositis requires a proactive approach to managing environmental triggers—especially sunlight. As Dr. Victoria Werth advises, “Sun protection is not optional for those who live with dermatomyositis—it’s essential. With the right precautions, patients can significantly reduce flares and improve their quality of life.