Sun rash on legs
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Your skin sure does take the brunt of summer’s hot, humid and sunny weather.
Too much sun can cause a rash. Too much heat can cause a rash. But what’s the difference, how do you treat them and how do you avoid getting them?
Melinda Cooling, vice president of Advanced Practice Providers at OSF HealthCare and chief clinician executive for OSF Saint Gabriel Health, breaks it down for us.
Heat rash
Heat rash, also known as prickly heat, often occurs during hot, humid weather. This rash usually appears in areas where the skin folds or areas where clothes causes friction like armpits, elbow creases, or the groin area.
“This type of rash often is not related to sun exposure but rather when blocked pores trap sweat under the skin,” Melinda said. “A patient may have small blisters or a deep lump that can feel prickly or itchy.”
Other than the hot humid weather, heat rash can develop due to:
- A lot of physical activity
- Illness with fever
- Tight or warm clothing
- Bandages
- Medicine patches that stick to the skin
Treatment
“Most of the time, heat rash will resolve on its
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Polymorphic light eruption
Polymorphic light eruption is a fairly common skin rash triggered by exposure to sunlight or artificial ultraviolet (UV) light.
Symptoms of polymorphic light eruption
An itchy or burning rash appears within hours, or up to 2 to 3 days after exposure to sunlight.
It lasts for up to 2 weeks, healing without scarring.
The rash usually appears on the parts of the skin exposed to sunlight, typically the head, neck, chest and arms.
The face is not always affected.
The rash
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The rash can take many different forms (polymorphic):
- you may get crops of 2mm to 5mm raised, pink or red spots, but redness may be harder to see on brown and black skin
- some people get blisters that turn into larger, dry patches – it looks a bit like eczema
- less commonly, the patches look like a target or "bulls-eye" (it looks a bit like erythema multiforme)
Polymorphic light eruption can be easily mistaken for heat rash (prickly heat).
Prickly heat is caused by warm weather or overheating
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Am I Allergic to the Sun? What You Need to Know About Sun Rashes
As the days grow longer and the warmth of the sun beckons us outdoors, it’s important to remember that while sunshine offers many benefits, it can also pose risks to our skin. While most of us are familiar with sunburns and the importance of sunscreen, there’s another potential danger that often goes overlooked: sun rashes. You may have a sensitivity to the sun if you take certain medications, use certain products or have a genetic predisposition.
What are Sun Rashes?
Sun rashes, also known as sun allergy or photodermatitis, are skin reactions triggered by exposure to sunlight. They can show up as red, itchy bumps, blisters, or patches of inflamed skin. These rashes typically occur within minutes to hours of sun exposure and can persist for days.
Types of Sun Rashes:
Polymorphous Light Eruption (PMLE)
This is the most common type of sun rash, affecting individuals who are sensitive to sunlight. PMLE usually appears as itchy or burning red patches or small bumps on sun-exposed skin. While it ca
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