Sunlight can have both positive and negative effects on acne. For some people, especially those with inflammatory acne, there is a dramatic improvement in the skin over the summer, when the days are longer and they spend a longer period outdoors.
Sun exposure works to suppress the growth of acne-aggravating P.acnes bacteria. Sunlight in the narrow 410 to 420 nanometer wavelength range (or violet-blue range) is efficient at killing P.acnes. The porphyrins that are part of the P.acnes bacteria are very sensitive to sunlight especially in the narrow 410 to 420 nanometer range. This discovery has led the FDA to approve the blue light acne therapy lamp that emits that type of light as an acne and wrinkle treatment.
The sun’s ultraviolet light waves also depress the immune system, which may lead to some improvement in acne by retarding the movement of white blood cells and reducing inflammation. When exposed to sunlight, our skin manufactures Vitamin D. What’s more, sunbathing for a good tan camouflages skin imperfections due to the pimples.
However, do not fall for the belief that the sun cures acne. Will sunburn help cure acne? The answer is no. The drawbacks of sun exposure far outweighs any potential advantages. The sun has a drying effect. Ultraviolet rays ultimately do far more harm than good by altering the DNA in skin cells, setting the stage for premature aging, ugly age spots and possible skin cancers. The heat and the sweating that often accompany sun exposure can also make acne worse for some people.
Tanning, the skin’s protective response to sun damage, also thickens the stratum corneum (the outer layer of the epidermis), adding to the load of skin cells filling your follicles and creating new comedones. And there is evidence that sunlight may stimulate oil production. Laboratory studies has shown that ultraviolet radiation may increase the size of sebaceous glands.
Collagen formation is also affected, which means that the marks left behind from any healing acne lesions will take longer to disappear and will even have a higher chance of leaving a permanent scar. If you have been put on oral antibiotic, isotretinoin (Accutane), Differin or Retin-A acne treatments, all the more you will need to stay out of the sun to prevent skin damage.
To minimize the risks of the sun worsening your acne when you have oily skin, choose an oily skin sunscreen such as sunscreen in a gel formulation. You can also use SPF-tinted moisturizers that help to conceal the acne while protecting your skin from the sun’s damaging rays. Products that combine acne treatments with sun protection are readily available in nearby stores.