Psoriasis and the Sun – Helpful or Harmful?
August 17, 2023 | Rheumatic Disease
In August, we recognize Psoriasis Awareness Month to raise awareness of this common chronic inflammatory autoimmune condition of the skin that impacts over 8 million Americans.
This condition has many different variants, the most common being chronic plaque psoriasis, which presents as red plaques with overlying gray or silver-colored scales. These skin lesions result from increased production of skin cells and increased activity of immune system cells that contribute to inflammation. While normal skin cells have a turnover time of 28 days, psoriasis skin cells have a shortened turnover time of only four days, which often results in thick plaques.
Risk factors for psoriasis include genetics, smoking, obesity, alcohol use, and stress. Certain medications and infections have also been suggested to trigger the onset of psoriasis.
There are many treatments for psoriasis, including topical ointments and creams, oral pills, injectable medications, infusions, and ultraviolet light therapy, a remedy that sunlight naturally provides.
Healing Powers of Sunlight
Sunlight can offer relief for psoriasis symptoms, as many patients report improvement in their plaques in the summer months or if they live in sunny climates.
Why is this? Sunlight emits ultraviolet rays, called UVA and UVB rays. UVB rays help to reduce the rate of skin turnover and can have anti-inflammatory effects. UVA rays, however, are harmful and penetrate deeper layers of the skin, which lead to skin tanning and skin aging. Sunscreen helps to block out UVA rays.
Ultraviolet light therapy is a powerful treatment option for patients with psoriasis. UV light treatment can consist of narrowband UVB therapy, broadband UVB therapy, or UVA therapy in conjunction with psoralen, a compound that helps prepare the skin for UVA waves. Depending on a patient’s needs, doctors will prescribe tailored treatment plans that are delivered via a special light box.
Notably, tanning beds are not an effective or recommended treatment for psoriasis, as these beds primarily use UVA light.
How Much Sunlight Is Enough?
A week at the beach will likely only provide mild, temporary benefits, but gradual long-term exposure may provide longer-lasting results. On the other hand, too much sun can exacerbate psoriasis skin plaques. So how much is enough?
First and most importantly, it is imperative to wear broad-spectrum sunscreen to block out harmful UV rays that can lead to burns, skin cancers, and skin damage. The National Psoriasis Foundation recommends sunscreen that is SPF 30 or greater, is fragrance-free, and made for sensitive skin. UV rays are most powerful between 10:00 AM and 4:00 PM, so start with five minutes of exposure around noon and build up gradually to about 30 minutes daily.
What Other Benefits Can I Get from Sunlight?
Getting a daily dose of sunlight has been shown to improve overall health by reducing stress, improving sleep by regulating circadian rhythm, and helping improve mood and mental health. In addition, sunlight helps to increase vitamin D levels, which is important for skin and bone health, is involved in the regulation of our immune system, can help reduce inflammation, and may improve psoriatic lesions.
Talk to Your Doctor
If your doctor has prescribed phototherapy as a treatment for your psoriasis, then natural sun exposure should be limited to prevent skin sensitivity. If you have severe, extensive psoriasis, you may need additional therapies, along with sun exposure, to help improve your skin condition.
If you have any questions regarding how to start incorporating sunlight into your day or questions regarding your psoriasis, reach out to your physician for help and guidance.