How can you tell them apart?
| Clue | Sunburn | Sun rash |
|---|---|---|
| Feel | Hot, tight, painful or tender; itching is also possible. | Itching is common in sun allergy reactions. |
| Appearance | Redness, swelling and later peeling; deeper burns cause blisters. | Small raised bumps, blisters or hives, depending on the reaction. |
| Timing | Pain starts within hours and usually peaks around 24 hours. | Timing depends on the reaction: tattoo sun allergy can start within minutes or hours. |
| Pattern | Skin exposed to too much UV light. | Some reactions affect particular areas, such as tattooed skin or exposed ears. |
Blisters are not a reliable dividing line because both burns and sun reactions can produce them. Sunburn can be harder to see on darker skin, so pay attention to heat, tenderness, peeling and blistering rather than redness alone.12
What kinds of sun rash are there?
Polymorphic light eruption, often shortened to PMLE, is a sun allergy rash with several possible appearances. Juvenile spring eruption is probably a localised form: it usually affects exposed ears in boys and young men during early spring. Itchy red lumps develop into blisters and crusts, appearing 8 to 24 hours after exposure and healing in about two weeks. A clinician can treat this with topical steroids and moisturisers, and prescribe antihistamines for itching.3
A sun allergy on tattooed skin can cause swelling, redness, tiny itchy bumps, blisters or hives whenever sunlight hits the tattoo. Clothing can protect a tattoo from sunlight, giving the wardrobe a skincare role it did not apply for.2
What should you do now?
For sunburn, start care as soon as you notice it:
- 1Get out of the sun, preferably indoors.
- 2Cool the skin with a cool shower, bath or damp washcloth, then gently pat dry.
- 3Apply a moisturiser containing aloe vera or soy while the skin is damp, and again when discomfort returns.
- 4Drink extra water because sunburn draws fluid towards the skin and can cause dehydration.
- 5Leave blisters intact. Keep them clean and protect them with petroleum jelly.
Avoid creams containing benzocaine or lidocaine, which can cause irritation or allergic contact dermatitis, an itchy reaction to something touching the skin. If itchy bumps keep returning after sunlight exposure, arrange a medical assessment rather than assuming they need burn treatment. Some medicines, including certain antibiotics, retinoids and diuretics, increase sunburn risk.135
A mild sunburn usually heals in a few days to a week; a blistering burn can take weeks. Do not pick peeling skin or pop blisters.1
When should you get medical help?
Seek prompt medical care for widespread blistering, severe pain or swelling, fever, chills or faintness. Worsening redness, pain, swelling or pus can signal infection. Confusion, loss of consciousness or seizures need emergency care. Severe dehydration also needs urgent assessment, especially if you cannot urinate or feel dizzy.16
Where this answer comes from
- 1Sunburn: Symptoms & Treatmentmy.clevelandclinic.org
- 2Tattoos: 7 unexpected skin reactions and what to do about themaad.org
- 3Juvenile spring eruptiondermnetnz.org
- 4How to treat sunburnaad.org
- 5Differences Between Sunburn vs. Sun Poisoninghealth.clevelandclinic.org
- 6When To See a Doctor for a Sunburnhealth.clevelandclinic.org
- 7Sun Exposure | Sunburn | UV raysmedlineplus.gov
