Blisters on the back from sunburn. A young guy on vacation at the beach caught fire from the rays of the sun. Reddened back. Ultraviolet rays. Global climate warming.
Blisters on the back from sunburn. A young guy on vacation at the beach caught fire from the rays of the sun. Reddened back. Ultraviolet rays. Global climate warming.

Have water blisters from sunburn? Here is everything you need to know on how to treat and prevent small sunburn blisters

May 27, 2022

Blisters, also known as bullae, are pockets of fluid between the epidermis (top layer of skin) and the dermis (second layer of skin). There are two common types of blisters people are likely to experience: blood blisters and “water” blisters. Blood blisters are pockets of blood and fluids that occur when the blood vessels are damaged, but the skin isn’t broken for it to come out. Water blisters come about in various ways but, despite their name, they contain more than water. These blisters are filled with serum or plasma from the blood and lymphatic fluid. The clarity and water-like consistency of the liquid is a good sign that the blister does not contain pus and is free of infection. Though common, blisters can pose serious health risks.

What can cause blisters?

Blisters are typically the body’s response to some form of skin or soft tissue damage, meaning they can pop up as a reaction to various injuries or agitators. Some common causes of blistering include:

  • A rub or friction injury, such as from a shoe
  • Burns, such as friction burns, thermal burns, chemical burns and frostbite
  • Radiation burns or severe sunburns
  • A drug reaction
  • An allergic reaction

At Burn and Reconstructive Centers of America (BRCA), our nationwide burn and wound teams treat the continuum of blister injuries. Due to BRCA’s specialized services, our experts treat a variety of blisters associated with burn injuries. In most cases, blistering can occur after suffering a second-degree burn. This burn severity appears as red, moist skin with signs of blistering. They are typically quite painful and tender to the touch. Second-degree burns with blistering can occur after a severe sunburn (radiation burn), spilling a cup of hot coffee (thermal burn), coming into contact with a caustic chemical (chemical burn), getting a shock from an electrical outlet (electrical burn) or staying outside too long in the cold unprotected (frostbite).  Some second-degree burns risk developing into third-degree burns over time and should be examined by a medical professional to assess and diagnose.

How should you treat or care for water blisters from sunburn?

There is some controversy surrounding the preferred treatment method and whether the blister should be broken or remain intact. Some medical professionals believe that blisters are an immune response and that the fluid-filled sack is there to provide cushioning and promote the damaged tissue’s healing process. However, others believe that stagnant fluid can breed infection. So, should you pop sunburn blisters or leave them be? If the blister is intact, it is not recommended to break it. While some believe stagnant fluid breeds infection, an open wound opens the door for harmful bacterial colonization. If the blister is already broken, have no fear! With proper wound care and good hygiene, the wound should heal within a week.

Proper wound care of a broken and intact blister is essential for quick, complication-free healing. If the blister is intact, you may not want to cover it at the risk of breaking it. However, that doesn’t mean you can’t cover it. A loose-fitting sterile wrap or a medicated, soft blister bandage should provide good protection and not cause further damage. However, for a broken blister, your main goal should be to keep the wound bed as sterile and debris-free as possible. Before messing with it, you should wash your hands with soap and water. Once your hands are clean, gently clean the broken blister with gentle soap and tepid, slightly warm water. Spread some antibacterial ointment on a gauze pad or sterile bandage and cover the wound. This dressing should be changed every day or as it gets dirty or wet.

When should you call the doctor?

Though blisters are common, they cause quite a lot of trouble for those with underlying health issues, immune disorders or comorbidities. A doctor should be consulted immediately if:

  • The blister is large, or if there are multiple blisters.
  • The blister no longer appears “watery” (clear, liquid and soft) but appears filled with pus (cloudy and firm). This may indicate the onset of infection.
  • The blister does not heal within a week. This may indicate a chronic or non-healing wound.
  • The blister is in a place that interferes with functionality (on the feet or hands).
  • There is blistering in unusual places, such as the mouth, eyelids or genital area.
  • There is blistering following antibiotic treatment (may be a sign of SJS/TEN or a severe allergic reaction) or radiation treatment (may indicate radiation burns).
  • The wound begins to change color, or you notice a foul odor.
  • You become feverish.
  • You develop a rash.
  • The skin around the edge of the blister starts expanding, which could mean cellulitis

How can you prevent sunburn from blistering?

The best way to prevent a sunburn from blistering is to prevent the sunburn from happening. Once a severe sunburn occurs, there is no way to prevent the blistering process. From there, all you can do is manage the blisters and the sunburn until they heal. To help prevent sunburn or the development of small sunburn blisters, take the following precautions:

  • Thirty minutes before going outside, apply sunscreen.
  • If you are sweating profusely or participating in a water activity during your time outside, make sure to reapply sunscreen as needed.
  • Sunscreen should be used even if it’s cloudy or overcast. Clouds help to block some UV rays but not all of them. It is important to remember that even if it is not hot or sunny outside, you are still susceptible to getting a sunburn.
  • For those with fair skin, thin hair or light-colored eyes, try to cover up with a hat, long-sleeved shirt and sunglasses.
  • Limit tanning both outside and in tanning booths.
  • Even if you plan on being in the shade, you should still wear sunscreen. It is possible to get sunburned from indirect sunlight.
  • Be cautious of antibiotics! Some antibiotics can increase sun sensitivity and cause severe sunburn within a very short time. The same goes for some acne treatments and chemical peels. Please read the warning label before participating in outdoor activities.

Further Information

Radiation burns, such as sunburns, can cause damage to the cellular structure of the skin and lead to cell mutations or cancer. Some people are more likely to get skin cancer and hyperpigmentation than others. If there is a history of skin cancer in your family, avoid prolonged exposure to UV rays and always wear UV protection such as sunscreen, hats and sunglasses.

To learn more about radiation burns, click here.

For information on toddler sunburns, click here.

For information on burn care ointments, click here.

For information on homeopathic burn remedies, click here.

For information on burn infections, click here.

For more information about BRCA’s services, physicians and locations, please visit or call (855) 863-9595.