What Makes Your Skin Red After A Sunburn?

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If you’ve ever whiled away an entire summer afternoon in the sunshine, without a care in the world, then you’ve probably experienced the painful consequence of your actions—a dreaded sunburn. Depending on your time spent outside, where you live, and what shade of skin you have, sunburns might be a more prevalent problem for you, but everyone in the world is vulnerable to the harsh effects of the sun.

Melting Nazi at the end of Indiana Jones movie Raiders of the Lost Ark

For those who have experienced a sunburn—and felt like a sensitive-skinned lobster for a few days afterwards—a common question arises… why does getting a sunburn make your skin red?

To dig into this question thoroughly, we must look into the basic science behind a sunburn.

The Science of a Sunburn

As most of you know, the beams of sunlight that illuminate the world and warm our skin are a form of electromagnetic radiation—visible light—but that’s not all. Sunlight also contains something called ultraviolet radiation. This radiation, unlike visible light, is able to penetrate the skin, getting into the very nuclei of the cells in your body’s largest organ. This UV radiation is broken up into two distinctions, UVA and UVB. The former penetrates deeper into the skin and is closely linked to aging and wrinkles, while the latter is directly linked to DNA damage and various forms of skin cancer.

When your skin is exposed to ultraviolet radiation, i.e., sunlight, for extended periods of time, the DNA in your skin cells can become damaged. This damage will lead to the production of different proteins, such as cytokines and prostaglandins, which trigger the immune system in the next 3-4 hours, notifying it that damage is being done to the body. The body’s immune response kicks into high gear, bringing inflammatory molecules and opening the blood vessels in that area, which results in the redness and discomfort associated with a sunburn.

I swear I was wearing sunscreen meme

If you get a rather deep, extended or intense sunburn, you may even begin to “tan”, which is the ultimate goal of those people who spend hours baking on beaches around the world. This tan is actually the body attempting to defend itself against additional radiation damage; melanin is a pigment that protects against incoming radiation, essentially reflecting the radiation away from the body. This natural sunscreen isn’t found in high levels in those people with light skin, which is why they are easily sunburned, and why they struggle to ever achieve a true “tan”. Given this information about melanin, many people with darker skin assume that they are safe from prolonged sun exposure, but that isn’t the case. Even people with very dark skin will suffer from a “sunburn” and damage to their skin cells, even if the skin doesn’t turn an obvious shade of red!

Effects of a Sunburn

You probably know the basic effects of a sunburn—or are currently experiencing them right now, hence your reading of this article—but there are some other long-term effects that people often overlook.

When the redness, itchiness and discomfort of a sunburn first appear, 4-6 hours after exposure to the sun, this is a sign that your body has responded to the threat and is working to repair the damaged cells. However, as is often the case, the sunburned skin cells will be too damaged, and may already be dead, in which case they will be sloughed off and removed from the body, in order to make room for new, healthy cells to form. This is why bad sunburns will peel or even blister during the healing process. Remember, even if your skin peels off, it doesn’t mean that all the damaged cells have been removed. The deep damage done by UVA and UVB rays can linger—for years! The DNA that is mutated in cells that aren’t eliminated by the body will increase your risk of developing skin cancer in the long run.

before and after ladyNot only does long-term exposure to the sun and frequent sunburns boost your chances of skin cancer in the future, but it will also speed the aging process. If you are noticing the early onset of wrinkles on your face, or others parts of your body regularly exposed to the sun, you are already seeing its effects! By damaging those deeper levels of your skin, UVA radiation will be able to compromise skin elasticity over time, making you look older than you really are, not to mention the unsightly sunspots and marks that can often develop over years of sun-soaking.

Ways to Prevent a Sunburn

The most obvious way to protect against a sunburn is to avoid long exposure to the sun, but that isn’t realistic for most people, who enjoy being social and active in the daytime, particularly on sunny, warm days! Therefore, taking common-sense precautions against sun exposure is your best bet—and something you should take seriously!

To begin with, wearing the right type of clothing is key; always bring a hat and sunglasses if you know that you’re going to be hiking around a mountain all day; and be sure to bring a loose cover-up for an extended barbecue on the beach. Don’t be afraid to soak up some shade from time to time in the midst of a long day; this will also help to avoid dehydration and other summer-related afflictions!

go outside is my pale skin memeMost importantly, using and reapplying sunscreen is critical to protecting your skin. Most people recommend using an SPF 30 or higher when out in the sun, and reapplying every two hours is suggested. Depending on your specific lifestyle, skin color, tan level or activity schedule, you must decide how and when to apply sunscreen, but it should certainly play some part in your daily skin protection routine!

A Final Word

Now that you understand why the skin gets red—increasing blood flow and the presence of melanin as part of the immune response to cellular damage—you can also understand why it’s so dangerous to allow yourself to burn in the sun! Taking care of your body and thinking about your long-term health may not be ideal brain fodder for a lazy day at the beach—but it should be!


  1. Scientific American
  2. Live Science
  3. University Of Iowa Hospitals & Clinics
  4. Springer
  5. Healio
The short URL of the present article is: http://sciabc.us/dOjmp
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About the Author:

John Staughton is a traveling writer, editor, publisher and photographer who earned his English and Integrative Biology degrees from the University of Illinois. He is the co-founder of a literary journal, Sheriff Nottingham, and the Content Director for Stain’d Arts, an arts nonprofit based in Denver. On a perpetual journey towards the idea of home, he uses words to educate, inspire, uplift and evolve.

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