First Aid Heat & Cold Exposure Sun Blisters? Here's What to Do By Jennifer Sabour, MS Updated on May 24, 2023 Medically reviewed by Leah Ansell, MD Medically reviewed by Leah Ansell, MD LinkedIn Leah Ansell, MD, is board-certified in cosmetic and medical dermatology. She is an assistant professor at Columbia University and works in private practice in New York City. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents What Causes Sun Blisters? Symptoms Treatment Prevention Sun blisters are small fluid-filled bumps that appear on seriously burned skin. They are caused by a sunburn, which is a type of radiation burn due to overexposure to ultraviolet (UV) radiation from the sun. Karen Poghosyan / Getty Images There are three degrees of sunburn that are based on the size and depth of burned skin. The higher the degree, the more severe the burn is. Sun blisters are second-degree burns, which affect the epidermis (outer layer of the skin) and dermis (layer below the epidermis that includes blood capillaries and nerve endings). As such, they can be highly painful. This article will explain the symptoms and treatments for sun blisters and when to seek medical attention. First-, Second-, and Third-Degree Burns First-degree burns, which are typically mild, only affect the epidermis, or outer layer of the skin. Second-degree burns affect the epidermis and dermis, which is the layer of skin below the epidermis. Third-degree burns, which are the most severe, destroy the epidermis and dermis. In some cases, they may also damage bones, muscles, and tendons. What Causes Sun Blisters? Sun blisters are a sign of a second-degree burn resulting from prolonged exposure to the sun's UVA and UVB radiation. The severity of your burn depends on your skin type, the amount of time your skin is exposed to the sun, the intensity of the sun at the time of exposure, whether you wear protection (sunscreen), and more. Sun blisters usually appear a few hours after sunburn occurs, but they can take up to 24 hours to develop. When to Get Immediate Medical Care Second-degree sunburns can be just as serious as burns caused by a fire or chemical exposure. Seek immediate medical care if blisters cover more than 20% of the body or the symptoms fail to improve after two days. Burn Blisters: What to Do and What Not to Do Sun Blister Symptoms It can take fewer than 15 minutes to get a sunburn. The type of symptoms you experience depends on the degree of burn. Without protection, your symptoms may be more severe. Sunburn The symptoms of sunburn depend on the depth of the burn. Common symptoms of first-degree (superficial) burns include: RednessSwelling of the skinDry, itchy, and peeling skinPain Common symptoms of second-degree (partial thickness) burns include: BlistersDeep rednessSevere pain (usually painful to the touch)SwellingWet and glossy skinSevere itch Common symptoms of third-degree (full thickness) burns include: White, black, or charred skinNo pain (due to destruction of nerve endings) Sun Poisoning Sun poisoning is not a medical term but it is often applied to an extreme case of sunburn that requires medical attention. Symptoms can include: Large blistersHeadachesFeverDizziness or confusionFaintingDehydrationNausea or vomitingRapid pulse and breathing How to Get Rid of Sun Blisters While most cases of sun blisters can be treated at home, seek medical attention if your symptoms do not improve within a week. Home Remedies Common home remedies to treat sun blisters include: Keep the skin moist: Keep the blistered area moist by lightly applying petroleum jelly (such as Vaseline or Aquaphor), aloe vera, or moisturizing cream. You can also cover it with gauze coated in petroleum jelly (don't use dry gauze). Drink extra water: Blistering skin can cause water loss. Drinking extra water prevents dehydration and assists with wound repair. Use a cold, damp compress: Use a compress to reduce swelling and redness in the sunburned area. Don’t pick or pop the blisters: This significantly increases the chance of infection and can cause damage to the skin that could lead to scarring. Take a pain reliever: Advil (ibuprofen) or Tylenol (acetaminophen) can reduce swelling and discomfort. Aspirin may be used, but only by adults. Avoid sun exposure while healing: If you need to be outdoors, wear protective clothing to cover your skin and apply sunscreen with a minimum of SPF 30. Long-Term Sun Exposure Over time, excessive sun exposure can lead to skin damage, premature skin aging, and skin cancer. If you have a history of severe sunburns, you are 2.4 times more likely to develop squamous cell carcinoma and 1.5 times more likely to develop melanoma. How to Treat a Sunburn When to See a Healthcare Provider Seek immediate medical attention if you display any of the following symptoms: Blisters that cover more than 20% of your body: To prevent widespread infection, your healthcare provider will examine the extent and degree of your burn to determine the best course of treatment for your recovery. Fever, nausea, chills, or headaches: These are symptoms of sun poisoning. Depending on the severity of your burn, treatments may include intravenous (IV) fluids for dehydration, topical antibiotics (Neosporin, Bacitracin, Polysporin) to prevent infections, and oral steroids (prednisone) or topical steroids (hydrocortisone) to reduce pain and swelling. Your blisters turn yellow or red over time: This could indicate an infection that may require antibiotics. Preventing Sun Blisters You should always try to avoid sunburn. Sunburns age skin cells and increase the risk of solar lentigo ("liver spots") and skin cancer. Prolonged sun exposure (especially during the summer) is associated with all major forms of skin cancers, including basal cell carcinoma, squamous cell carcinoma, and melanoma. To reduce the risk of sun damage, avoid going out into the sun between 11 a.m. and 4 p.m., when the UV index (a calculation of the intensity of the sun's UV radiation) is at its highest. If you have to be outdoors, apply a broad-spectrum sunscreen (which protects against UVA and UVB radiation) that's at least SPF 30 and water-resistant. Wear protective clothing (including a hat and sunglasses) and reapply sunscreen every two hours and after swimming. Summary Sun blisters are a sign of second-degree burns from prolonged exposure to the sun. They can appear in a few short hours after exposure or take up to 24 hours to develop. Symptoms of second-degree sunburn include the formation of blisters, deep redness, and severe pain. While most cases of blisters can be treated at home, seek immediate medical attention if blisters cover more than 20% of the body. At-home remedies include drinking extra water, applying soy or aloe vera moisturizer, using a cold, damp compress, and taking a pain reliever. Sunburn ages skin and increases the risk of skin cancer, so take preventive steps to reduce your sun exposure. While it's best to plan ahead so you don't get a sunburn, it can happen due to unexpected circumstances. Get out of the sun at the first signs of redness. While sunburn is common, it can also be a serious condition, especially if it has reached the point of blistering. 7 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Skin Cancer Foundation. Sunburn & your skin. Johns Hopkins Medicine. Burns and wounds. Johns Hopkins University. Sunburns. Northwestern Medicine. Quick dose: When should I see a doctor for sunburn? University of Pittsburgh Medical Center. Sun poisoning dangers: symptoms, treatment, and prevention. Wu S, Cho E, Li WQ, Weinstock MA, Han J, Qureshi AA. History of severe sunburn and risk of skin cancer among women and men in 2 prospective cohort studies. Am J Epidemiol. 2016;183(9):824-33. doi:10.1093/aje/kwv282 MedlinePlus. Liver spots. Additional Reading Holman DM, Ding H, Guy GP, Watson M, Hartman AM, Perna FM. Prevalence of sun protection use and sunburn and association of demographic and behavioral characteristics with sunburn among us adults. JAMA Dermatology. 2018;154(5):561-568. doi:10.1001/jamadermatol.2018.0028 See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit