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Sun can alter your DNA

As we get the long days underway, we cannot ignore the need to protect our skin.

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DR. Vikas Sharma

As we get the long days underway, we cannot ignore the need to protect our skin. Continued and repeated sun exposure can cause permanent damage to your skin. As the ultraviolet radiation exposure accumulates over a lifetime, the radiation can cause DNA changes, which can show up as actinic keratosis and pigmentary skin disorders.

In addition to the changes that can result in keratosis and skin cancer, sun damage can lead to age spots, redness from broken capillaries, diffused hyperpigmentation, wrinkling, and altered skin texture.

Cyclic damage

The cycle of sun damage starts with the absorption of the UV radiation into the skin. UVA rays penetrate deeper into the skin than UVB rays. The radiation then triggers activity in the skin cells. We see this activity through the darkening of the skin’s pigment. If the skin continues to be exposed to this damage over time, the DNA can be damaged. If the DNA is damaged and begins to send the wrong signals to the cells, the incorrect cell division process that results can cause skin disorders.

Prevention better than cure

A regular regimen of sunscreen, moisturizers and exfoliation can help with early, superficial signs of skin damage. Sunscreen helps shield the skin by creating a barrier between the skin and the UV rays. But sunscreen’s effects can be nullified if not used correctly. 

Polymorphous light eruption: This manifests as skin rash over the exposed areas to the sun. It becomes very itchy at times. To avoid it one should not go out in the sun between 12 noon to 3 pm as the harmful UVB rays are at its peak during this time.

Photocontact dermatitis: Always be careful not to immediately go out in sun after applying fragrances and hair colours with paraphenylene diamine as the risk of an attack of photocontact dermatitis becomes 40-fold higher during this season.

During the summers, extra precautions are must for patients suffering from chronic skin disorders like Lupus Erythematosus and Rosacea as these can have an acute exacerbation and thus even may require hospitalisation.

Sunscreens a must

Sunscreens work by absorbing, reflecting or scattering the sun’s rays on the skin.  They are available in many forms, including ointments, creams, gels, lotions and wax sticks.  All are labelled with SPF numbers.  But SPF does not reflect how good a sunscreen is for your skin. Efficacy of sunscreen should not be assessed by the SPF number but by the constituents it has. It should be a broad-spectrum sunscreen having both physical and chemical barrier effects. Broad-spectrum sunscreens block out both the UVA and UVB rays. 

When to use it

Sunscreens are best applied about 20 minutes before going outdoors. This gives your skin time to soak in the sunscreen.  All types of sunscreens, even water-resistant sunscreens, are more effective if reapplied ideally after three-hour interval.

How much is enough 

Your skin is effectively protected if 2 mg/cm 2 layer of sunscreen has been applied. This literally means ½ teaspoon (3ml) to each arm, to the face and the neck. More than a teaspoon (6ml) is needed for application to each leg, the chest and back. It should also remain on your skin when you sweat,  swim or during long periods of exercise. The ideal choice for sunscreen is the one that effectively blocks both UVB and UVA rays, which is done with an SPF of 15 or greater. It should also be non-toxic, water-resistant and importantly hypoallergenic & non-comedogenic.

(Dr Sharma is a Chandigarh-based dermetologist)

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