Managing Sunburn: What is It and Why Does Skin Remain Red After Sunburn?

What causes sunburn?

The sun emits different types of radiation, which have specific effects on your skin. UVA rays can penetrate deep into the skin, causing significant damage over time. These rays are present throughout the day and can pass through clouds and glass. UVA rays are associated with skin aging, such as wrinkles and age spots, as well as contributing to the development of certain types of skin cancer.¹

UVB rays are most intense between 10 a.m. and 4 p.m. and are mostly responsible for sunburn. They also play a role in the development of skin cancer.³ UVB rays vary in intensity depending on factors such as your location, time of day, and altitude.¹

How does sunburn damage your skin?

When the skin is exposed to excessive amounts of UV-radiation from the sun, or artificial sources like tanning beds, a series of reactions within the skin cells are triggered, which indirectly damage the DNA of these cells.^3,4

Why does your skin turn red after sunburn, and why does sunburn hurt?

To repair damaged cells, the body initiates an inflammatory response. This response leads to the classic symptoms of sunburn, such as pain and redness, which is often accompanied by warmth and tenderness, and in severe cases swelling and blistering.⁴ Blisters can be very painful.

The severity of a sunburn depends on the intensity and duration of UV exposure and the level of sun protection you use, however, skin tone can also be a factor. Fair or light-skinned people can burn more easily due to less melanin in their skin, which is a protective pigment.⁴

Why can sunburn appear purple?

Over time, UV damage to the skin can lead to a condition known as solar purpura or actinic purpura. Solar purpura is more commonly observed in older people, as it is a long-term consequence of chronic UV damage. Approximately 12 percent of people above the age of 50 are affected.⁵

This condition is characterized by the appearance of small, flat, purple or red spots on the skin. They predominantly appear on areas of the body that receive significant sun exposure, such as the back of the hands, forearms, neck, and face. The blood vessels under the skin's surface weaken, which makes them more prone to rupture and leakage. As a result, small amounts of blood seep into the surrounding tissue, leading to the typical purple spots seen in solar purpura.⁵

What are other effects of sunburn?

Sunburn not only causes immediate discomfort, but also poses long-term risks to our health. Prolonged or intense exposure to UV radiation damages the DNA within our skin cells, increasing the likelihood of developing cancerous cells. Melanoma, the most dangerous form of skin cancer, is particularly associated with sunburn and unprotected sun exposure. If you experience five or more sunburns, or only one single blistering sunburn, it approximately doubles your risk of developing melanoma later in life.⁶

Sunburn also accelerates the aging process of the skin, as the harmful UV rays break down the collagen and elastin fibers that give our skin its elasticity and firmness. As a result, sunburns can lead to development of wrinkles, fine lines, and age spots.^1,6

Since sunburn damages the outermost layer of the skin, it can also lead to peeling, dryness, and flakiness and in some cases, the skin may develop discoloration or uneven pigmentation.

If you have severe sunburn, and you feel cold, tired or nauseous, you may have heatstroke, so it’s important to seek medical attention.⁷

Why is sunscreen important in skincare?

When to apply sunscreen in skincare routine?

How to deal with sunburn?