Science Wednesday: how sunburns happen

Madeline Bombardi

Summer is ending and fall is upon us. The days of lounging by the pool are over, tan lines are set for winter and our sunburns have fully recovered.

The warm sensation of sun rays beating against our skin is welcomed — just not the sensitive, itchy red aftermath. Why is it that our skin becomes a peeling, overly-sensitive, bright red tomato?


As our skin is exposed to the sun, ultraviolet rays are absorbed and begin to damage the surface layer of skin. Ultraviolet light is short wavelengths invisible to the human eye, according to “Ultraviolet Waves,” an article published on Mission: Science by NASA.  It states that UV-B rays are the most harmful rays for humans, because they are responsible for sunburns.

Adam Hadhazy, a writer for the online website Livescience, explained how UV rays damage skin cells.

He stated UV-B  waves damage the skin’s DNA by breaking the nucleotides, adenosine, thymine and guanine bonds. These bonds give your DNA its overall shape and structure.

Although sun exposure damages our skin, skin tissue has built-in “sun screen” to deflect these UV rays. This natural defense mechanism is a pigment produced in the body called melanin.

When the temperature receptors in our skin detect sun exposure, the melanin is pushed toward the affected cells and acts as a barrier to protect them. The melanin takes in the UV waves and disperses it as heat. Hence why we can feel hot on a cool, but sunny day.

Alan Curtis, a public health graduate student, stated, “I was actually reading about this last week. … The sun’s UV light kills skin cells so the immune system sends blood and white blood cells to the area to get rid of dead cells.”

Alan is absolutely right. Prolonged sun exposure will cause excessive harm to unprotected cells. The overly-damaged skin cells will die. The body rushes blood to this area to assist in healing. This is why the sunburned skin turns bright red and becomes inflamed.

Over time, dead skin cells are shed as new ones are formed, causing the snake-like peeling effect.

As these new cells are forming and the old dying, the outermost layer of skin laden with nerve fibers is ferociously firing signals to the brain. These fibers are extremely sensitive and continually signal to the brain that there is something touching the skin until the healing process is complete. These nerve fiber signals are the cause of the unrelenting itch.

There are a variety of home remedies to care for mild sunburns which include: oatmeal infused lotion, which helps with inflammation, counteracting the itchy feeling and gently removing dead skin cells while promoting healing growth, ibuprofen for inflammation and cold showers to alleviate the “hot” feeling.


Most dermatologists state that the best remedy against the sun is to stay hydrated, maintain moisturized skin and stay protected with a zinc-based lotion.

Collegian Science Beat Reporter Maddy Bombardi can be reached at or on Twitter @madelinebombard.