Burned and Blistering? When To See a Doctor for a Sunburn

Leaving a severe sunburn untreated can lead to dehydration and heat-related illness
zoom in on sun-blistered shoulder

You spent the day at the beach, frolicking in the waves, and all you have to show for it (besides sand everywhere) is a giant sunburn. Uh-oh. Do you need to worry?

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“There are many health problems that can stem from sunburn,” says dermatologist Amy Kassouf, MD. “You don’t need to see your healthcare provider for every sunburn. But getting medical care when needed can prevent some of those serious conditions from developing.

“Sunburns are similar to thermal burns — the kind caused by touching hot surfaces, liquids, steam or flames,” she explains. “They don’t go as deep as thermal burns but are more damaging to your DNA.”

Dr. Kassouf shares the dangers of severe sunburn, how to know if you have one and when to seek medical care.

Severe sunburn requires medical attention

A small patch of first-degree sunburn (the least severe type) doesn’t typically cause serious health issues. But as your skin continues to react to ultraviolet (UV) radiation, you may develop concerning symptoms. See your provider if you have:

  • A first-degree burn all over your body, which increases the risk of developing a heat-related illness.
  • Large area of blistered skin, which increases the risk of infection.
  • Symptoms of sickness or dehydration, such as fever, chills or faintness.

“Blistering skin means there’s more damage in the deeper layers of your skin,” Dr. Kassouf says. “You’re more likely to dehydrate, become feverish and develop inflammation. That’s when you need to seek medical care.”

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Can sunburn make you sick?

You can develop health issues from a second-degree sunburn. These include:


Badly burned skin no longer holds moisture in your body, so you may dehydrate. Signs that you’re severely dehydrated include:

  • Dry mouth or thirst.
  • Inability to pee (urinate) or dark-colored urine.
  • Constipation.
  • Disorientation or confusion.
  • Dizziness, especially when rising to stand.
  • Exhaustion.
  • Headache or confusion.

Sun poisoning

Sun poisoning is like an allergic reaction to a sunburn. Essentially, the extreme exposure to UV radiation causes skin inflammation. The main difference between sun poisoning and a typical sunburn is the additional symptoms you may develop with sun poisoning, including:

  • Burning sensation.
  • Chills.
  • Extreme thirst.
  • Itchiness.
  • Nausea.
  • Rash.

Heat exhaustion

You don’t need to be in extreme heat to develop heat exhaustion, notes Dr. Kassouf. Severe sunburn causes a loss of body fluids that can lower your blood pressure and your blood volume. The first symptom is fatigue. In addition to feeling tired, you may also experience:

  • Dizziness.
  • Intense thirst.
  • Feeling faint.
  • Fever.
  • Headache.
  • Sweating heavily.


Heatstroke happens when your body can no longer control its temperature. The condition can cause permanent disability or even death if not treated quickly. It typically begins as heat exhaustion, but the symptoms rapidly worsen and may include:

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  • Extreme sweating or hot, dry skin (if dehydrated).
  • Loss of consciousness.
  • Mental impairments such as confusion and slurred speech.
  • Seizures.
  • Very high body temperature (over 104 degrees Fahrenheit or 40 degrees Celsius).


“The danger of developing an infection typically greater a few days after the burn, when the blisters are breaking and there are exposed lower layers of skin,” Dr. Kassouf explains. Telltale signs of infection can include:

  • Increase in redness, pain, and swelling.
  • A severe fever.
  • A covering of pus or crust over the open site.  

Why it’s important to seek medical care for a sunburn

Don’t ignore the early signs of dangerous sunburn. See your provider if you have any signs of dehydration, sun poisoning, heat exhaustion or heatstroke. The symptoms of these health conditions go far beyond sunburn discomfort, can last much longer — and may even cause lasting damage.

“When your sunburn is serious, your skin is no longer a strong protective barrier for your body,” Dr. Kassouf reiterates. “You might develop symptoms of heat-induced trauma, such as dehydration, low blood pressure and shock. But it all starts with the sunburn.”

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