Sunscreen protects from skin damage
Monsoon has arrived and humidity is at its peak. Sunscreens and sunblocks are in huge demand. Rightly so, as we need to take care of our skin. Markets are flooded with a variety of them and everyone is confused. Physicians too, are overwhelmed with queries on the kinds of sunblocks and the usage. So, let me start by explaining some of the common terms.
What is Sun Protecting Factor (SPF)?
SPF refers to the ability of a cream or lotion to block the sun’s harmful rays. SPF15 means you can be in the sun 15 times longer than you could have without the sun screen before getting sun burns. SPF number on the product also reflects product’s ability to screen Ultra Violet Rays (UVR). In terms of the absorbing ability of the cream for UVR the classification is as follows: SPF2 will absorb 50 percent of UVR; SPF15 absorbs 93 percent UVR; SPF 34 absorbs 97 percent and SPF50 absorbs 98 percent of UVRs.
UVRs are of two types: Ultra violet A Rays (UVA) and Ultra violet B Rays (UVB); UVA penetrate deeper into the skin and cause premature ageing and wrinkles whereas UVB cause sun burns, cancer, cataracts and even weaken the immune system.
FDA has approved a variety of sunscreens and based on ingredients they can be classified as the following:
• UVA absorbers include avobenzone, ecamsule, meradimate
• UVB absorbers include paraamino benzoic acid (PABA), cinoxate, ensulizole, octinoxate, salicylates
• UVA and UVB absorbers include dioxybenzone, oxybenzone, sulizobenzone
• UVA and UVB physical sunscreens contain titanium dioxide, zinc oxide
How to choose sunscreen?
Generally SPF15 is sufficient for a casual exposure for short durations (a few minutes). Higher SPFs, however, is needed if exposure is prolonged. Sunscreen must be repeated every two hours.
• For children’s skin: UVR are more damaging in younger skins as the skin is thin and delicate, has less melanin and is immunologically immature. It is advisable to avoid direct sun exposure to infants. Sunscreen should be applied on the infant’s face and back of hands where protection from clothing is inadequate. PABA and oxybenzone have been associated with skin reactions. Physical sunscreens such as zinc oxide and titanium oxide tend to be better tolerated by kids’ skin.
• Adolescents: Youngsters with acne should avoid sunscreens with alcohol, PABA and oxybenzene. They should use zinc oxide and titanium based non-greasy sunscreens. Creams are greasy whereas gels and lotions are non-greasy. Acne medication makes skin more sensitive to sun damage and hence, it is more important to use sunscreens.