Skin damage from UV exposure can start within 10 minutes, hours before the first sign of redness shows up. You can see sunlight and feel its heat, but UV radiation itself is invisible, which is why it damages skin even on cool, overcast days.

Sunburn is graded in three degrees, based on how deep the damage runs: first, second and third degree burns respectively.

At least two in three Australians will be diagnosed with skin cancer by age 70, and every sunburn, even a mild one, adds to that risk. Australia’s summer UV index is among the highest in the world, which is a large part of why. Read more on why Australia has such a high skin cancer rate.

This guide covers what each degree of sunburn looks like, what it does to your body beyond the skin, when it stops being a home-care problem, and how to actually prevent it.

What Are the Different Levels of Sunburn

Sunburn is classified by how far the damage reaches into the skin, not by how painful it feels on the day. It usually shows first as redness within a few hours, then continues developing for 24 to 72 hours before healing begins.

First-degree sunburn

Damage is limited to the epidermis, the skin’s outer layer. Expect redness, pain and warmth to the touch, with peeling as the skin heals over the following days. Most first-degree sunburn is manageable at home.

Second-degree sunburn

Damage reaches the dermis, the layer beneath the epidermis. Blistering, intense pain and swelling are the main signs, and some people also get fever, chills, nausea or fatigue. This level needs medical attention to prevent infection and support proper healing.

Third-degree sunburn

True third-degree burns, full destruction of the skin and the fat layer beneath it, almost never come from sun exposure alone. What gets described as “third-degree sunburn” is usually a severe second-degree burn. Genuine third-degree damage typically involves a chemical or heat source on top of sun exposure, and it is a medical emergency requiring immediate hospital care, not home treatment.

The Impact of Sunburn

Sunburn damage does not stop at pain and peeling. Each burn causes DNA damage in skin cells, which accumulates over a lifetime and raises skin cancer risk with every repeat exposure.

The skin itself changes over time too, including irregular pigmentation and visible capillaries that leave permanent redness. Recurrent UV exposure over time can also accumulate damage to the eyes, and can contribute to early onset of cataracts and macular degeneration.

None of this requires a severe burn. Mild, repeated sunburn causes the same long-term damage as one serious burn, just spread across more occasions.

When to See a Doctor – Treatment

See a doctor the same day if blistering covers a large area, or if fever, chills, nausea or confusion appear alongside the burn. These are signs the body is responding to more than surface damage.

Get medical attention immediately if skin looks white, waxy or leathery, or if the burn site has become numb rather than painful. That combination points to deeper tissue damage and should not wait.

For infants and young children, see a doctor for any sunburn with blistering, since children burn faster and more severely than adults. The same applies to anyone whose sunburn is not improving after a few days, or shows signs of infection such as increasing pain, swelling, or discharge from broken skin.

Visit our sun damage and Photoageing page to learn more.

How to Avoid Sunburn – Prevention

1. Apply broad-spectrum SPF 30+ sunscreen 15 to 30 minutes before going outside, and reapply every two hours or after swimming or sweating.
2. Wear protective clothing, a broad-brimmed hat and UV-protective sunglasses.
3. Seek shade and avoid direct sun between 10 am and 4pm, when UV is strongest.
4. Take extra care near water, sand and snow, which reflect UV and increase burn risk.
5. Certain medications including commonly used antibiotics for acne management may increase sun sensitivity, and it’s good to know from the pharmacist or your doctor if your medications make you more sun sensitive.
6. Stay hydrated, particularly during long periods outdoors.

Elixir @ Hunter is a skin cancer clinic in Maitland, treating patients from across the Hunter and Newcastle region. If sunburn keeps happening, or you have not had your skin checked recently, book a consultation with one of our doctors.