What are red spots from the sun?

The most common cause for red spots is sunburn, but a condition called polymorphous light eruption (PLE) or heat rash might be to blame as well.
The most common cause for red spots is sunburn, but a condition called polymorphous light eruption (PLE) or heat rash might be to blame as well.

Spending a day outdoors is healthy and fun. But the fun can be cut short if you get too much sun and end up with a burn or rash. Too much sun exposure can lead to several different problems. One commonly known danger is the risk of skin damage or skin cancer after too much sun exposure. But there are short-term risks from being in the sun as well, one of which is sunburn.

Sunburn is a common result of too much time in the sun. However, what does it mean when your skin develops a rash after sun exposure? Can sunburn give you red spots on your skin? Learn more about what the sun can do to your skin and how to protect yourself.

Symptoms of red spots from the sun

Being out in the sun can lead to painful discomfort on your skin. Although all skin types can get sunburn, people with fair-skin are more susceptible and typically experience redness on the skin as a result of sun damage. Redness can appear fairly evenly in swatches or large patches, or it might look like a series of spots.

The most common reason for redness is sunburn, but a condition called polymorphous light eruption (PLE) or heat rash might be to blame as well. Depending on which you’re experiencing, the spots on your skin may look a little different.

Sunburn

Symptoms of sunburn can include redness, which might be worse in places if the skin blisters — an indication of a serious sunburn. You might also experience dryness, itching, and possibly peeling after a few days.

Polymorphous light eruption (PLE)

Your skin could develop red spots from the sun because of a condition called polymorphous light eruption (PLE). PLE causes a spotty red rash or hives. This condition is an allergic reaction to the sun. It isn't usually dangerous, but it can be uncomfortable.

Heat rash

Heat rash often looks like a cluster of pimples or small blisters — in other words, little raised spots. They can feel itchy and may appear red on people with fair skin.

Causes of red spots from the sun

Red spots from the sun can be caused by sunburn, PLE, or heat rash. Even though these causes are all related to sun or heat, they happen for different reasons.

Sunburn

Sunburn is no different from a burn you might get from touching a hot stove. It can range from mild to severe. The sunburn will heal, but the damage from repeated sunburn adds up over time. Repeated sunburns raise your risk of skin cancer later in life. They can also lead to wrinkles and dark spots on your skin.

Polymorphous light eruption (PLE)

PLE is an allergic reaction to the sun's ultraviolet rays. It causes a blotchy, red rash on exposed skin. The rash can be itchy, and you may experience chills and fatigue as well. People tend to have PLE in the first part of the summer when they aren't used to sun exposure. However, it probably won't happen all summer. As the skin gets accustomed to the sun, it becomes less reactive.

Heat rash

Heat rash is another type of itchy or painful skin reaction you might get in hot weather. However, it isn't caused by sun exposure but temperature. Heat rash can even show up in spots that were covered up. Clothing or other skin coverings cause sweat glands to get blocked. The blockages result in itchy red bumps or blisters.

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When to see the doctor for red spots from the sun

Typically, you can treat PLE, heat rash, and sunburn at home. However, if the redness lingers or seems to be getting worse, you should call a doctor. Look for signs of infection like increased pain, swelling, and new or worsening redness.

Sunburn

With sunburn, if your skin blisters or if you have a fever and chills along with the burn, call a doctor right away.

Polymorphous light eruption (PLE)

You should call your doctor if PLE symptoms don’t go away after you’ve tried home treatment. Even if PLE does go away with home treatment, you might want to talk to a doctor. It can happen more than once during the sunny months, and your doctor might be able to help you prevent future eruptions.

Heat rash

In most cases of heat rash, you won’t need to see a doctor. Getting out of the heat and cooling down should ease the symptoms. But if it’s not getting better after 3 to 4 days, or if it seems to be getting worse, check with your doctor to be sure it’s not caused by an infection.

Diagnosis of red spots from the sun

Your doctor will examine the area of your skin where you have the red spots. They will have questions about how long you have had symptoms, when the burn or rash first appeared, and what kind of sun exposure you had.

Treatments for red spots from the sun

Depending on what caused your sun reaction, your doctor will choose an appropriate treatment.

Sunburn

Cold compresses reduce swelling from sunburn. Ask your doctor about creams with soothing ingredients such as aloe vera or prescription burn ointments. If the burns have blisters that have become infected, you might need antibiotics.

Polymorphous light eruption (PLE)

Treating PLE is like treating an allergic reaction. Steroid creams can help heal the rash in the short term. Your doctor may also suggest ultraviolet therapy to "harden" the skin. This gets you used to the sun’s rays so you don't have reactions in the future.

Heat rash

You can treat heat rash with cold compresses. Your doctor might recommend over-the-counter treatments like calamine lotion or antihistamine creams. If it doesn't clear up or gets worse, see a doctor. If the rash is infected, you may need prescription-strength treatment for it.

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Medically Reviewed on 1/21/2021
References
American Academy of Dermatology: "How to treat sunburn."

American Academy of Family Physicians: "Heat Rash."

American Osteopathic College of Dermatology: "Polymorphous Light Eruption."

Johns Hopkins Medicine: "Sunburn."

Michigan Health: "How to Manage Your Summer Rash."

National Health Service UK: "Heat rash (prickly heat)."

Skin Cancer Foundation: "Sunburn & Your Skin."