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People with psoriasis often notice that their symptoms improve in the summer, when they have more sun exposure. This is no coincidence — the right amount of exposure can benefit a person with psoriasis.

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

These cells accumulate on the surface of the skin in scaly plaques that can be uncomfortable and itchy. Treatments include medicated creams, steroids, a range of oral medications, and biologic drugs, which target the immune system.

Sunlight may help manage skin symptoms, but it is important to take precautions because too much sun exposure can make symptoms worse or trigger a flare.

This article looks at how to have safe sun exposure with psoriasis and how to protect the skin from too much sun.

Sun exposure may have a positive impact on the symptoms of psoriasis. It also boosts vitamin D levels, which may or may not play a role in psoriasis.

UV rays

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Controlled sun exposure may help with psoriasis.

The sun emits ultraviolet (UV) rays, which can be UVA or 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.

Research suggests that UV rays have immunosuppressive effects, which can help reduce psoriasis symptoms.

Natural UVA rays alone do not appear to improve psoriasis symptoms, but UVB rays may help.

UVB exposure from the sun can slow the rapid growth of skin cells that occurs with psoriasis. This may help ease inflammation and reduce scaling in people with mild to moderate psoriasis.

Vitamin D

Sunlight can also help the body create vitamin D, which has many important functions in the body. Vitamin D occurs naturally in some foods, but a person needs sunlight for most of their vitamin D supply.

A 2017 review suggested that vitamin D deficiency may be common among people with psoriasis.

However, it is not clear whether increased vitamin D helps improve psoriasis symptoms or whether the improvement is due to sunlight benefitting the immune system.

Dermatologists may recommend that people with psoriasis use topical creams that contain vitamin D. These creams can help with psoriasis plaques.

Learn more about how vitamin D can help with psoriasis.

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Too much sun can cause skin damage and may trigger psoriasis.

Sunlight can help treat psoriasis, but it is important to increase exposure slowly and set limits to prevent any damage that may trigger a flare of skin involvement.

Before going into the sunshine, ensure that:

  • all the areas of skin affected by psoriasis will have equal exposure
  • all other areas are protected with sunscreen or clothing

Start by exposing affected areas for 5–10 minutes at the same time each day, such as at noon. This will allow the body to absorb sunlight and reduce the risk of sun damage.

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

It is best to work with a doctor, such as a dermatologist, to determine the right amount of sun exposure. They may recommend a more controlled type of UV exposure, such as narrow-band UVB therapy.

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

UVB rays may help treat psoriasis because they likely modify the immune system, which is not working correctly in people with psoriasis.

Doctors may also recommend PUVA, a combination light therapy.

The person will first take psoralen or its derivative, methoxsalen, to increase the body's sensitivity to UVA rays. Then they will undergo phototherapy.

Researchers have described PUVA as safe and effective, but many dermatologists prefer a safer alternative — narrow-band UVB therapy — because PUVA can increase a person's risk of skin cancer.

What are the different types of light therapy for psoriasis and how do they work? Learn more here.

If a person practices safe exposure, sunlight can help with psoriasis. But too much can result in further damage and worsening symptoms.

Skin cancer

Another risk of sun exposure is skin cancer. Those most vulnerable include children, people who do not protect their skin adequately, and those who experience sunburn.

Medications

Some medicines, 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 do not recommend that people with the condition 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, and this is especially true for people with psoriasis.

Sunscreen

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People with psoriasis should use a hypoallergenic sunscreen as sunlight can trigger symptoms.

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

For a person with psoriasis, a good sunscreen will:

  • have "broad-spectrum" on the label, indicating that it offers 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

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

Various hypoallergenic sunscreens are available to purchase online.

Other precautions

Below are some more tips for sun safety.

  • Wear a hat, pants, and a long-sleeved shirt to help protect the skin from too much sun exposure. Some clothes and hats are infused with sunscreen, and dermatologists highly recommend these.
  • Use sunglasses to protect the sensitive skin around the eyes.
  • Seek shade around midday by staying indoors or sitting under a tree, umbrella, or tent.

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, but sunlight can reflect off various surfaces, including snow and water. This can increase skin exposure.

There is currently no cure for psoriasis, but many people manage the condition with topical treatments and lifestyle changes.

Careful, limited sun exposure can help manage 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 make symptoms worse.

A dermatologist can help determine the best type and extent of exposure to UV rays and what type of sun protection to use.

XTRAC laser therapy is a more localized form of light therapy for psoriasis that targets the affected area directly and is useful for stubborn, small plaques. Learn more here.

Q:

What is a good time of day to try sun exposure if I have psoriasis? Does it work on cloudy days too?

A:

A person with psoriasis can have limited outdoor sun exposure as a treatment, but only under the care of a dermatologist.

The National Psoriasis Foundation suggest starting with 5–10 minutes of noontime sun daily. Even on a cloudy day, you will be exposed to UVB from the sun, although the rays may not be as strong.

Owen Kramer, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.