Yes, you can get a third-degree burn from the sun, though it’s rare. Most sunburns stay at the surface level, damaging only the outermost layer of skin. But in extreme cases, prolonged UV exposure can destroy tissue all the way through the deeper skin layers and into the fat beneath, meeting the clinical definition of a full-thickness (third-degree) burn. A study of sunburn patients admitted to burn centers in Australia and New Zealand found that 4% had full-thickness burns, while another 12% had deep second-degree burns that came close.
How Burn Depth Is Classified
Burns are categorized by how far the damage reaches into your skin. A first-degree burn affects only the epidermis, the paper-thin outer layer. It looks red, feels tender, and heals within a week. This is your typical mild sunburn.
A second-degree burn pushes into the dermis, the thicker layer beneath. This is where blisters form. Second-degree burns are further split into superficial and deep. Superficial ones heal in one to two weeks with minimal scarring. Deep second-degree burns take three weeks or longer to heal and carry a 70 to 80 percent chance of leaving a scar, because so little healthy dermis remains to regenerate from.
A third-degree burn destroys the epidermis and dermis entirely, reaching the subcutaneous fat. At this depth, the skin can no longer repair itself. The burned area often looks white, dull, or leathery rather than red, and it may feel numb because the nerve endings in the dermis have been destroyed. That numbness is actually a warning sign: if a burn doesn’t hurt, it may be deeper than you think.
What a Third-Degree Sunburn Looks and Feels Like
A third-degree sunburn doesn’t look like an ordinary sunburn. Instead of the familiar red, tender skin, you’ll see patches that appear white, waxy, or leathery. The skin won’t blanch (turn pale and then red again) when you press on it. Surrounding areas may still be painful, blistered, and inflamed, but the deepest sections can be strangely painless because the nerves are gone.
Systemic symptoms often accompany burns this severe. Expect chills, fever, nausea, dizziness, rapid heartbeat, and signs of dehydration like dry mouth and reduced urination. In the worst cases, heat stroke or shock can develop. These whole-body reactions are sometimes called “sun poisoning,” a term that captures how the damage goes far beyond the skin.
Why Some People Burn So Severely
Several factors can push a sunburn from uncomfortable to dangerous. The most obvious ones are duration and intensity: falling asleep on a beach at midday, spending hours on open water with UV reflecting off the surface, or being at high altitude where UV radiation is stronger.
Medications play a surprisingly large role. Nearly 400 different drugs have been identified as potentially photosensitizing, meaning they make your skin react more intensely to UV light. Common categories include certain pain relievers (NSAIDs), some antibiotics, blood pressure medications, and specific acne treatments. If you’re taking any of these and spend time outdoors, your skin can burn faster and deeper than you’d expect.
Fair skin, a history of frequent sunburns, and immunosuppression all raise your risk as well. Young children and infants are particularly vulnerable because their skin is thinner.
How Deep Sunburns Are Treated
Mild sunburns respond to cool compresses, aloe, and over-the-counter pain relief. Deep burns are a different story. For severe blistering sunburns, a doctor may prescribe a corticosteroid cream to control inflammation. If a blister breaks on its own, the standard guidance is to carefully trim the dead skin, wash the area gently, apply antibiotic ointment, and cover it with a nonstick bandage to prevent infection.
One thing that makes deep burns tricky is that they can worsen after you come out of the sun. Inflammation and reduced blood flow in the damaged tissue can cause the burn to deepen over the first 48 to 72 hours. A burn that initially looks like a moderate second-degree injury can progress into a deep second-degree or even third-degree burn during that window.
Third-degree sunburns that destroy full-thickness skin often require hospital care. Because the skin can’t regenerate on its own at that depth, surgical treatment such as skin grafting may be necessary. Recovery takes weeks to months and typically leaves permanent scarring.
When a Sunburn Needs Emergency Care
Head to an emergency room if you notice any of the following after sun exposure:
- Blisters covering a large area (more than 20% of your body, roughly a whole leg, your entire back, or both arms)
- White, waxy, or leathery skin that doesn’t hurt when touched
- Fever above 102°F (39°C)
- Signs of dehydration like dizziness, extreme thirst, or very little urination
- Signs of infection such as pus coming from blisters
- Symptoms of shock or heat stroke including confusion, rapid breathing, or fainting
Any sunburn on a baby under one year old also warrants immediate medical attention.
Long-Term Risks of Severe Sunburns
Even if a severe sunburn heals completely, the damage compounds over time. A single blistering sunburn during childhood or adolescence nearly doubles a person’s lifetime risk of developing melanoma. That statistic applies to second-degree blistering burns, not just the rarer third-degree ones. Photosensitizing medications add another layer of concern: some drugs linked to phototoxicity, including certain antibiotics and blood pressure medications, are also associated with an increased risk of skin cancer with long-term use, particularly in people who are immunocompromised.
Deep sunburns that take more than three weeks to heal carry high rates of permanent scarring and changes in skin pigmentation. The scarred tissue is also more sensitive to future UV damage, making the area more vulnerable going forward.