Retinoids are chemicals whose effect on the skin is similar to that of vitamin A (retinol). They may be obtained naturally or created synthetically. The outermost layer of the skin, called the epidermis, consists of a top layer of dead cells that act as a barrier to microorganisms and the environment and help in water retention. The top layer is a dynamic structure that also contains melanocytes, responsible for skin pigmentation, and Langerhans’ cells, which drive the skin’s immune response system against infections. Retinoids help to loosen or separate this top layer of the epidermis (the horny layer of the epidermis). By hampering the decomposition of collagen (the material making up the skin), retinoids allow for thickening of the layer of skin where wrinkles originate.
What skin issues are treated by retinoids?
Considerable evidence and practice has led dermatologists to recommend retinoid-based drugs to mitigate skin disorders such as psoriasis, acne and skin ageing due to overexposure to UV rays from sunlight. Retinoids can minimise the onset of wrinkles, decrease the rate of collagen breakdown, thereby regulating epithelial cell growth, reduce discoloration/pigmentation and maintain skin elasticity. Pigmentation is caused by a group of natural skin pigments called melanin. Retinoids suppress the production of melanin and hence reduce discoloration.
Effect on skin aging
Exposure to harmful ultra-violet radiation is the single biggest cause of skin aging. The skin ages naturally as epithelial regeneration rate slows down. But the effects of sunlight can be seen in a thickened epidermis and deep instead of fine wrinkles, blotchy dark spots, lax, dull and rough skin. Retinoids can halt the process of skin aging by fattening the layer of dermis which largely contains collagen. Collagen fibers give structure and tensile strength to the skin. They bind with elastin fibers to maintain skin elasticity and with water to keep the skin hydrated. Retinoids help prevent their breakdown by preventing the production of the enzyme collagenase that decomposes collagen after sun exposure.
Over the counter or prescription retinoids
Over-the-counter retinoids contain retinol, which is not as potent as prescription-based formulations containing retinoic acid. Retinol has to combine with other substances on the skin to turn into retinoic acid and hence avoids the initial redness and peeling of the skin that appears on first-time prescription retinoid usage. OTC retinoids may be more apt for those beginning this therapy for aging. Drugs prescribed by dermatologists contain tretinoin and retinoic acid that could be up to a hundred times more active than OTC retinoid.
Harmful effects of retinoids
Retinoid use may cause dryness and irritation on the skin, induce changes in skin colour, heat sensitivity, redness, swelling or blistering.
Precautions
To prevent these side effects, one should avoid direct sunlight, especially during warm weather, in the middle of the day. If sunlight is unavoidable, one should wear adequate sunscreen (SPF 30 or higher). Clothing that covers most parts of your body should be worn.
One should take precautions not to exceed prescribed quantities for use as advised by a certified dermatologist or as mentioned on the label for OTC retinoids.
The author is Consultant Dermatologist, Columbia Asia Hospital, Gurgaon
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