Why Sunscreen is Necessary

Do you love enjoying your time outside in the sunshine? But, do you take care of your skin in the meanwhile? If not, you must immediately start practicing proper protection from overexposure to the sun. Although the manufacture of vitamin D, a crucial component for building and maintaining healthy bones, depends largely on the sunlight (particularly ultraviolet B), one must never leave the skin unprotected from the UV radiation emitted by the sun, since it not only damages your skin, but also our immune system.

UV radiation (ultraviolet rays) is a part of electromagnetic energy, a product of nuclear radiation at the core of the sun, which travels to the Earth’s surface via its rays. These invisible rays can also be produced from artificial sources, such as lasers, black lights, and tanning beds. They are mainly made up of three types of rays—UVA, UVB, and UVC—among which, UVA and UVB are primarily responsible for skin damage.

While UVC is the radiation having the shortest wavelength among all UV rays, it is the most dangerous one. Fortunately, the ozone layer absorbs it, so it never reaches the Earth’s surface. However, it can still be found in artificial sources like welding torches and mercury lamps. UVB directly damages the skin’s DNA, besides causing delayed tanning, skin reddening, and blistering, and it can also be stated as the primary cause of sunburn. Likewise, UVA, being the radiation having the longest wavelength, is responsible for 95% of the UV radiation that reaches the Earth’s surface. It not only causes immediate tanning and sunburn, but also penetrates the inner cells, causing long-term effects like premature aging, wrinkles, and some skin cancers.

Regardless of the above UV rays having different effects on the skin, they are equally harmful to our body, and cause both acute as well as chronic responses, including photo damage (premature aging and wrinkling due to repeated unprotected exposure to UVR, primarily from the sun and also from artificial sources), immune-suppression, urticaria (red, itchy welts), erythema or sunburn, discoloration, melasma, tanning, and various types of skin cancers. It also accelerates the inflammation and redness of the skin, causes pimples to end up as dark scars, and results in fine lines and dry, coarse, and leathery appearance of skin, besides gradually reducing the skin’s elasticity.

The epidermis, the outermost protective layer consisting of hair, nails, and pores, contains the pigment-producing cells called melanocytes. These cells manufacture melanin, which basically acts as a barrier, reducing the penetration of UV rays into the skin through the epidermis by effectively absorbing it and neutralizing harmful radicals created by frequent exposure to sunlight before they cause subcellular damage. Otherwise, this subcellular damage incites a cascade of chain reactions that would potentially lead to skin cancer and premature skin aging. When the human body lacks melanin, in conditions such as vitiligo and albinism, they are prone to sunburn and skin cancers.

Melanocytes in individuals with darker skin tone produce melanin more actively than in individuals with lighter skin tone. Thus, it has been proven that darker skin pigmentation isn’t as prone to skin cancers due to sun exposure.
All these damages can be minimized with a daily adequate amount of sunscreen use. Sunscreen or sunblock contains physical (inorganic) and chemical (organic) compounds that play a vital role in preventing skin cancer. Inorganic compounds include zinc oxide and titanium dioxide, which shield the skin and reflect and scatter UV radiation, preventing the skin from the burn. Organic compounds, including oxybenzone and octinoxate, behave like sponges and absorb the UV light. Moreover, applying sunscreen daily also contributes to keeping our immune system in peak condition. It effectively maintains the skin texture, reduces small visible blood vessels and fine lines, and decreases the risk of skin cancers. It is one of the most effective ways of taking care of our skin and shielding it from toxic UV radiation.

When buying sunscreen, choose one that offers broad-spectrum protection. “There are filters in sunscreen that protect against only UVA, only UVB, or both UV A and B filters. So, when you buy a sunblock, look for the following words on the label: “UVA and UVB protection, PA +++ sign, broad-spectrum, and SPF”, to ensure UVA and UVB coverage,” says dermatologist Dr. Prativa Shrestha. “It is also recommended to use a sunscreen with an SPF of at least 30% for most children and adults as a part of the photoprotection strategy, since it blocks 97% of the sun’s UVB rays. But, if you spend time outdoors, mostly between 10 a.m. and 4 p.m., it is better to choose a sunscreen with an SPF of 60 or greater. This is because the sun’s rays are more powerful during this time, since they have to cover less distance comparatively.”

In the case of the skin’s vulnerability to redness, one should look for a sunscreen with more gentle ingredients like zinc oxide or titanium dioxide. These ingredients are “generally recognized as safe and effective” (GRASE) by the U.S. Food and Drug Administration (FDA). Zinc oxide and titanium dioxide are also processed into small particles to improve the texture and feel of the sunscreen, besides fulfilling the optical properties required for protection from UV radiation. It is never too early or too late to start taking care of your skin. Hence, applying sunscreen should be a part of your daily morning skincare routine.

Q & A with
Dr. Prativa Shrestha, Dermatologist

How often should we apply sunscreen?
Sunscreen should be applied to dry skin 15-30 minutes before going outdoors. Once you apply sunscreen, it forms a protective layer, but this protective layer only works for two hours; therefore, we should reapply every two hours for the best protection.

Is it necessary to apply sunscreen even if we are staying indoors?
Of course! UVA rays can penetrate windows and clouds and cause premature aging. Blue light emitted from smart devices and television affects the skin by stimulating melanin production and generation of free radicals, which causes premature aging. Even on a cloudy day, and if you are sitting by the window or in front of the computer for extended hours, you are advised to put on sunscreen.

Is sunscreen 100% effective in preventing skin cancers?
Sunscreen doesn’t provide 100% protection against UV radiation. However, it reduces the risk of skin cancers by preventing sunburn, which is one of the main predictors of all types of skin cancer.

Is there a difference between face and body sunscreen?
You can use the same sunscreen for your face and body. The face tends to be oilier than the body. Many prefer gel or lotion formulations for the face, and lotion, cream, or spray for the body.

Is tanning from the sun, and artificial sources like tanning beds, lasers, and black lights, bad for the skin?
Artificial tanning is not safer than the sun. According to the American Academy of Dermatology, one indoor tanning session can increase the risk of developing skin cancer (melanoma by 20%, squamous cell carcinoma by 67%, and basal cell carcinoma by 29%). It causes the early appearance of signs of skin aging, such as age spots, loss of skin firmness, and wrinkles.

Are there any ways to increase the production of melanin?
There is no safe way to increase melanin, as we already know that sun exposure can cause premature skin aging and skin cancers. In the case of vitiligo, we give medicines that help to regain melanin. But, one should keep in mind that melanin alone isn’t enough to protect your skin from sun damage. That’s why it is important to wear sunscreen and appropriate clothing whenever you’re outside.

What SPF is most suitable for the climate of Nepal?
A minimum of SPF 30 is recommended. The amount and frequency of sunscreen applied are as important as SPF. A general recommendation is two fingertip units for the face. Once applied, it works only for two hours. I would suggest applying the thickest possible layer of sunscreen and reapplying as frequently as you can.

What are the most common skin diseases in Nepal?
We see diverse skin diseases, but the commonest would be acne, melasma, fungal infection, urticaria, and eczema.

What is the worst case you’ve come across regarding skin disease caused by overexposure to the sun?
It is a photosensitivity reaction caused by oral medicine doxycycline in genetically identical twin sisters. Both had taken the medicine for acne. They developed large blisters on their arms and legs and had sun intolerance.

Lastly, what would you like to suggest to people about protecting their skin from harmful UV rays?
It is difficult to apply two fingertip units of sunscreen every two hours as recommended. I would suggest applying antioxidant serum, which will protect and repair skin, applying and reapplying the thickest possible layer of sunscreen, carrying an umbrella, and wearing protective clothing. An ounce of prevention is worth a pound of cure.

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