Sunburn Introduction

The sun provides the light and warmth that sustains life on Earth. However, as nearly everyone experiences, there can be too much of a good thing, especially when it comes to the sun on your skin.

Spending too much time in the sun leads to sunburn, which can range from painful and annoying, to potentially life threatening. Repeated exposure to the sun’s rays damages skin by accelerating the skin aging process and also increases the risk for developing skin cancer.

Fortunately, you can avoid sunburn and minimize your risk of sun damage to your skin by taking a few preventative steps.

Skin Overview

The skin is composed of two main layers: the epidermis and the dermis. The epidermis is the outer layer that acts as the body’s primary defense against the environment. The dermis, or innermost layer, provides structure and support to the skin.

Sunburn seriously damages cells in the epidermis, so it is useful to understand how this skin layer functions. The lowest layer within the epidermis, directly above the dermis, is called the basal layer. Cells produced here change and secrete important substances for the skin as they gradually move toward the surface and become the outermost, protective covering of the epidermis.

Basal layer cells exist with other cells called melanocytes. These cells produce melanin, which gives skin its pigmentation, or color. Melanin absorbs harmful rays of sunlight that would otherwise damage the cells. The body actually produces extra melanin in response to sun exposure, which causes tanning up to the point where the sun is too intense and a sunburn results.

The Sun’s Damaging Rays

The sun gives off energy waves that range from the highest energy associated with radioactivity and X-rays, to visible light, to invisible infrared light that we feel as heat, to microwaves and radio waves, which have the lowest energy. When it comes to sunburn, the waves we’re concerned with are invisible waves of ultraviolet, or UV, light.

Ultraviolet light is classified into three types: UVA, UVB, and UVC. Fortunately, UVC is completely blocked by air gases before it reaches Earth. UVA and UVB do pass through air to the ground, even passing through clouds, which is why you sunburn even on a cloudy day.

Approximately 95% of the ultraviolet light that penetrates your skin is UVA. This form is responsible for tanning, but it penetrates more deeply than UVB, and is an important factor in causing sun damage and skin cancers.

UVB accounts for about 5% of the UV light that affects your skin. Although it doesn’t penetrate as deeply as UVA, it has more energy and is the primary cause of sunburn.

Why Sunburn Occurs

Sunburn happens when so much UV light strikes the skin that the protective effect of melanin pigment is overwhelmed. Living cells in the skin layers are killed. As a result, your immune system increases blood flow to the dermis, which causes inflammation of the affected area.

The increase in blood flow brings in white blood cells that help remove dead cell debris. The extra blood is what causes the redness and warm sensation you feel with a sunburn.

UV light can also damage genetic material, or DNA, in the skin’s cells, which can lead to skin cancer.

A scale known as the Fitzpatrick classification indicates the degree to which certain skin types sunburn. Individuals with less melanin are highly susceptible to sunburn and those with more melanin don’t burn as easily.


Unlike instantaneous burns from touching a heat source, sunburn inflammation and redness usually start about four hours after exposure. Maximum redness generally occurs within 12 to 24 hours, and the painful, burning sensation occurs from 6 to 48 hours after exposure.

After a couple days, the outer layers of skin may peel away. Peeling is actually the body’s way of healing itself by shedding the top layer of damaged epidermis.

Severe sunburns can cause chills, fever, nausea, and blistering in various degrees. In cases in which people are stranded without shelter, extremely severe sunburns can cause what is known as sun poisoning. Sun poisoning may be life threatening. It results in severe blistering, a lack of fluids, an imbalance in important chemicals, and it may even lead to deadly infections.

Sunburn and Sun Damage Prevention

UV radiation damage is caused by both the intensity and length of sun exposure. Therefore, the best prevention is to avoid being caught unprotected if you are going to be in the sun for more than 20 minutes. When possible, avoid sun exposure from 10 AM to 2 PM, when the rays are most intense.

Because it is impossible to avoid all sun exposure you should use sunscreen and wear protective clothing when you are out in the sun. Dermatologists recommend using SPF 15 or greater, broad-spectrum sunscreens that block UVA and UVB.

Apply the recommended amount of sunscreen before sun exposure and again once in the sun. Reapply every two hours or when done toweling off after swimming.

In addition, a wide-brimmed hat provides even more protection than sunscreen for shielding the scalp, face, and neck regions. Long sleeved shirts and long pants made from tight-weaved materials also provide excellent protection from the sun.

Sunburn Treatments

Household treatments including soothing gels, cool compresses, cool baths, moisturizers, and anti-inflammatory medications such as aspirin or ibuprofen are often used to relieve the discomfort from a sunburn until it disappears with time. If blisters develop, don’t pop them because it slows the healing process and increases the likelihood of infection.

Some sunburns can require the help of a medical professional. Seek help if you feel sick. Skin care professionals can treat sunburns with creams that prevent burn infections, anti-inflammatory medications, fluids, pain relievers, and in severe cases, prescription corticosteroids may be used to reduce swelling and itching.

Extremely severe sunburns may require intravenous fluids to re-hydrate and restore a chemical balance to the body. Some cases may even require admission to a hospital burn unit.

Sunburn Recovery

Sunburns disappear and serve as a painful reminder of what happens when you spend too much time in the sun. Mild, general cases may take three days to over a week to clear.

Peeling will make way for new, unburned skin underneath, but may briefly leave the skin with irregular colored blotches. Peeling and blotchiness generally subside in a couple of weeks while your skin fades back to its normal color with no long-lasting, visible effects.

Remember, the key to retaining healthy, youthful skin and minimizing risks for skin cancer is to avoid unprotected and frequent sun exposure.