Key takeaways

  • Controlled sun exposure, under the guidance of a healthcare professional, may help alleviate psoriasis symptoms by leveraging UVB rays to reduce inflammation and slow skin cell growth.
  • However, while sunlight aids vitamin D production, which is often lower in individuals with psoriasis, it is not as effective as prescription phototherapy and carries risks such as skin damage and cancer.
  • When exposing skin to the sun, precautions like using broad-spectrum sunscreen with SPF 30 or higher, covering exposed skin with clothing, and avoiding peak daylight hours are essential to minimize risks.

Psoriasis is an inflammatory condition that can develop when the immune system is not functioning correctly. It results in an overgrowth of skin cells.

Some doctors may recommend regular exposure to sunlight as part of a psoriasis treatment plan. However, it is important to follow medical guidance.

Sunlight is not as effective for treating psoriasis as prescription therapies, and too much sun exposure can worsen symptoms or trigger a flare-up.

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Sun exposure may have a positive impact on psoriasis symptoms. It also boosts vitamin D levels.

UV rays

The sun emits ultraviolet (UV) rays: UVA and UVB. The difference lies in the size of the wavelength. UVA rays can reach deeper into the skin, while UVB rays do not penetrate as deeply.

As a result, UVA rays from sunlight are less effective in treating psoriasis than natural UVB rays.

Exposure to natural UV light may ease inflammation and reduce scaling in people with psoriasis. However, doctors do not recommend using sunlight to treat psoriasis in all cases. People should never do so without appropriate medical guidance.

Further, sunlight is not as effective for treating psoriasis as prescription phototherapy.

UV light therapies are a well-established treatment for chronic psoriasis. Targeted UV light can reduce psoriasis symptoms and slow down skin cell growth.

Vitamin D

Sunlight can also help the body create vitamin D, which has many important functions. Vitamin D occurs naturally in some foods, such as oily fish. However, people need sunlight for most of their vitamin D supply.

A 2023 review suggests that vitamin D levels are significantly lower in people with psoriasis than in those without. However, the role that vitamin D plays in psoriasis management is controversial.

More research is necessary to understand whether low vitamin D levels may contribute to psoriasis or occur as a symptom of the condition.

Sunlight may help relieve psoriasis symptoms. However, people should only use it if their primary care professional recommends it.

A medical professional can assess a person’s medical status and advise on the safest level of sun exposure.

For example, some doctors may recommend always wearing sunscreen when outside or avoiding peak daylight hours. The Environmental Protection Agency states that the sun’s rays are typically strongest between 10 a.m. and 4 p.m.

Doctors may also recommend a more controlled type of UV exposure, such as narrow-band UVB therapy.

Anyone who is undergoing phototherapy should avoid sun exposure. This includes people who use PUVA, a light therapy that involves a combination of UVA rays and a drug called psoralen.

Phototherapy refers to UV light exposure in a controlled setting, such as a dermatologist’s office. During phototherapy, the skin absorbs UV rays. This can help ease psoriasis symptoms.

UVB rays may help treat psoriasis by slowing rapidly growing skin cells, reducing inflammation, and relieving itching.

Phototherapy may reduce or resolve immediate symptoms of psoriasis in 50% to 90% of cases. However, phototherapy will not fully cure the condition, and symptoms may return.

Doctors may also recommend PUVA, a combination light therapy.

The person will first take psoralen to increase the body’s sensitivity to UVA rays. Then they will undergo phototherapy.

Although healthcare professionals typically consider light therapy safe and effective to treat psoriasis, a 2019 review highlights that PUVA is a less common treatment option.

This is because it increases the risk of squamous cell carcinoma — a type of skin cancer — especially after 350 sessions. Therefore, many dermatologists prefer narrow-band UVB therapy.

Sun exposure can damage the skin and cause skin-related diseases. Below are some risks people should be aware of.

Skin cancer

Sun exposure is a risk factor for skin cancer. Other risk factors for skin cancer include:

Medications

Some medications, including oral medications, topical creams, and ointments, can make the skin more sensitive to light. This can increase the risk of sunburn and other forms of skin damage.

It is important to ask a healthcare professional about any risks associated with medications and other treatments.

Tanning beds

The National Psoriasis Foundation does not recommend that people use tanning beds to treat their symptoms.

Unlike phototherapy units, tanning beds use wavelengths that can damage the skin and increase the risk of skin cancer.

Tanning beds may also use more UVA than UVB light — another reason why they are less effective than phototherapy at reducing psoriasis symptoms.

Anyone who seeks sun exposure should protect their skin. People with psoriasis should always consult their primary care physician before doing so.

Sunscreen

There are different types of sunscreen, and it can be difficult to choose the right one.

For someone with psoriasis, a good sunscreen may:

  • have “broad-spectrum” on the label, indicating protection from both UVA and UVB rays
  • have a sun protection factor (SPF) of at least 30
  • be water-resistant, if a person will be swimming or sweating under the hot sun
  • be hypoallergenic or designed for sensitive skin and possibly fragrance-free

Water-resistant sunscreens must state on the label whether they remain effective for 40 or 80 minutes when swimming or sweating. All sunscreens should have instructions on when to reapply to ensure maximum protection.

Some chemicals in generic sunscreens may irritate the skin or trigger flares.

Other precautions

Below are some more tips for sun safety.

  • Cover exposed skin: Clothing can help protect the skin from too much sun exposure. This may include shirts with long sleeves and wide-brimmed hats.
  • Use sunglasses: Using sunglasses can help protect the sensitive skin around the eyes.
  • Seek shade: Shade can help to limit sun exposure and allow the body to cool.

However, be aware that there is still a risk of excessive sun exposure in shady areas. Trees and umbrellas can block some of the sun’s rays. However, sunlight can reflect off various surfaces, including snow and water. This can increase skin exposure.

Sun exposure under medical supervision may help someone manage their psoriasis symptoms, primarily through the action of UVB rays. Phototherapy in a dermatologist’s office provides a more controlled form of exposure to these rays.

It is important to undergo light therapy under the supervision of a qualified professional. Tanning beds are not a safe alternative.

Take precautions when exposing the skin to sunlight, as too much sun can worsen symptoms. A dermatologist can help determine the best type and extent of exposure to UV rays and what type of sun protection to use.