Sun poisoning goes beyond ordinary sunburn. If your skin is blistered, you feel nauseous or dizzy, or you’re running a fever after time in the sun, you’re likely dealing with sun poisoning rather than a standard burn. The term isn’t a formal medical diagnosis, but it describes a severe sunburn that causes whole-body symptoms, not just red, tender skin.
Sun Poisoning vs. Regular Sunburn
A regular sunburn makes your skin red, warm, swollen, and tender. It’s uncomfortable, but the effects stay at the surface. Sun poisoning shares all of those skin symptoms but adds a layer of systemic reactions, meaning your whole body starts responding to the damage.
The key signs that push a sunburn into sun poisoning territory include:
- Blisters on the burned skin
- Severe pain that goes beyond typical tenderness
- Nausea or vomiting
- Fever and chills
- Headache
- Dizziness or lightheadedness
- Rapid heartbeat
- Fatigue
- Dehydration (dark urine, dry mouth, extreme thirst)
If you have red skin plus any combination of those symptoms, that’s the clearest signal you’re dealing with sun poisoning. The more of those symptoms you check off, the more serious the reaction.
What It Feels Like as It Develops
Sun poisoning doesn’t always announce itself right away. Your skin may feel fine while you’re still outside, then steadily worsen over the next several hours. Redness and pain typically intensify before blisters start forming. The whole-body symptoms, like nausea, chills, and dizziness, can develop alongside the skin changes or show up slightly later as your body ramps up its inflammatory response.
You might notice you feel oddly cold despite having been in the heat all day. Chills and shivering are common with sun poisoning and catch people off guard because they seem counterintuitive after sun exposure. This happens because your body is mounting a fever response to the widespread skin damage, similar to what happens with a bad infection. Confusion, shortness of breath, and fainting represent the more extreme end of the spectrum and signal that you need medical attention quickly.
Why Some People React More Severely
Fair skin burns more easily, but sun poisoning can happen to anyone with enough exposure. Several factors make a severe reaction more likely, and the biggest one people overlook is medication. Dozens of common drugs increase your skin’s sensitivity to UV light, sometimes dramatically. These include ibuprofen and naproxen, certain antibiotics (especially doxycycline and other tetracyclines), blood pressure medications, common antidepressants, acne treatments like isotretinoin and tretinoin, and some diabetes medications. If you’re taking any prescription or even certain over-the-counter drugs, check the label for photosensitivity warnings.
Other risk factors include being at high altitude or near reflective surfaces like water, sand, or snow. Time of day matters too. UV intensity peaks between 10 a.m. and 4 p.m., and you can burn through clouds. People who haven’t had much recent sun exposure are especially vulnerable, which is why sun poisoning commonly hits early in the summer or on vacation.
Sun Allergy Reactions That Mimic Sun Poisoning
Not every severe reaction to sunlight is a burn. Some people develop a rash called polymorphous light eruption, which appears as dense clusters of small bumps, raised rough patches, or tiny blisters. It typically shows up 30 minutes to several hours after exposure and tends to affect areas that are usually covered by clothing, like the upper chest, front of the neck, and arms. The rash is itchy or burning and can occasionally come with fever and chills. It looks different from person to person, which is part of what makes it tricky to identify on your own.
A rarer condition called solar urticaria causes hives, stinging, and redness within minutes of sun exposure. Unlike a sunburn, these hives appear quickly and fade within minutes to a few hours once you’re out of the sun. If your skin reacts this fast and resolves this quickly, you’re likely dealing with a true sun allergy rather than sun poisoning.
Both of these conditions can look similar to other skin diseases, some of them serious. If you repeatedly develop rashes after sun exposure, a dermatologist can run a phototesting exam, which uses a special lamp to see exactly how your skin reacts to different wavelengths of light. A photopatch test can determine whether a substance on your skin (like a medication or topical product) is triggering the reaction. In some cases, blood tests or a small skin biopsy may be needed to rule out underlying conditions like lupus.
What Happens Inside Your Body
The reason sun poisoning makes you feel sick all over is that severe UV damage triggers a massive inflammatory response. Your immune system floods the damaged skin with blood and immune cells, which is what causes the swelling, redness, and heat. When the damage is widespread enough, that inflammatory response spills over into your whole body, producing fever, fatigue, and nausea.
Dehydration is the other major concern. Severe blistering pulls fluid out of your bloodstream and into the damaged skin. When blisters pop and the skin opens, you lose fluid and electrolytes directly. This fluid loss, combined with the fact that most people were already somewhat dehydrated from being in the sun, can lead to a rapid heartbeat, dizziness, and lightheadedness. Open blisters also create a pathway for bacteria, raising the risk of skin infection.
How to Manage Sun Poisoning at Home
Get out of the sun immediately and move to a cool, shaded environment. Drink water or an electrolyte drink steadily, not just when you feel thirsty. Cool compresses on the burned skin can help with pain, and lukewarm (not cold) baths or showers are gentler on damaged skin. Aloe vera gel can soothe the surface. Avoid popping blisters, as intact blisters protect the raw skin underneath and reduce infection risk.
Over-the-counter pain relievers can help with pain and inflammation. Loose, soft clothing prevents further irritation. Stay out of the sun entirely while you’re healing, which typically takes longer than a normal sunburn. Expect peeling, and resist the urge to pull loose skin off, as it can tear healthy skin beneath it.
Signs You Need Medical Help
Some cases of sun poisoning need professional treatment. According to Harvard Health, you should see a doctor if blisters are accompanied by bright red or oozing skin, severe pain, fever, shivering, headache, or nausea and vomiting. Any bleeding or oozing from the burned area could signal infection and warrants immediate attention.
Confusion, fainting, and shortness of breath are the most urgent red flags. These suggest severe dehydration or heat-related illness on top of the skin damage. Large areas of blistering also increase the risk of dangerous fluid loss, similar to what happens with a thermal burn. If you’re unsure whether your reaction is serious enough to warrant a visit, the general rule is simple: if your sunburn is making you feel sick beyond just skin pain, get it checked.