Exposure to ultraviolet radiation (UV) from the sun is one of the notable factors that affect the skin. Many people consider it non-poisonous and a much-wanted temporary tan. Nevertheless, prolonged unprotected sun exposure can lead to protracted skin damage. Skin exposure to UV radiation may vary depending on the skin type, as the amount of melanin differs among different skin types.
The connection between UV radiation and skin damage
According to Dr Asmita Dhekne Chebbi, MBBS, MD Dermatology, Apollo Spectra Hospital, Bangalore, UV rays are categorised into three distinct types: UVA, UVB, and UVC. Most of the UVC rays are absorbed by the ozone layer and therefore have minimal penetration to Earth’s surface. However, UVA and UVB rays get to the surface and penetrate the skin to a certain degree.
UVA enters deeply into the skin, while UVB initially affects the epidermis. UVA rays enter deeply into the dermis and will result in premature ageing and permanent pigmentation changes. UVB rays are the key contributors to sunburn, as they initially affect the outermost layer of the skin. Both can cause DNA damage and can increase the risk of skin cancer.
Difference between tanning and pigmentation
The effect of tanning lasts for a short period, during which the skin darkens in response to UV radiation as a protective mechanism. The specialised cells, melanocytes, which produce melanin, will further enhance their manufacturing to safeguard the deeper skin layers against the damage caused by UV rays. This action also indicates that the skin is already under stress.
Pigmentation problems occur due to the continuous or constant exposure to UV rays, and they result in skin conditions such as:
- Melasma: Leaves brownish-grey spots, mainly on the face.
- Solar lentigines: Hyperpigmented macules (dark spots)
Unlike tanning, which may fade over time, pigment changes may either become permanent or lead to degeneration without proper healthcare.
The impact on different skin types
Skin types are categorised into six, with Types I and II considered very fair, Types III and IV as medium fair, and Types V and VI as darkly pigmented, respectively.
- Type I and Type II (Fair skin): Compared to the other types, a lesser amount of melanin is present in these two skin types, which can easily get burnt and tan very badly. Following prolonged exposure to UV radiation, individuals may experience extreme redness, sunburn, and lasting DNA damage. This population is very susceptible to contracting skin cancers like basal cell carcinoma or melanoma.
- Type III and IV (Medium skin): These skin types are prone to pigmentation issues; they tend to tan easily and experience less frequent burns. The most common diseases among these skin types are melasma and uneven skin colour, particularly when exposed to the sun.
- Type V and VI (Dark skin): A Higher amount of melanin is found in these skin types and therefore provides natural photoprotection. They are, however, prone to hyperpigmentation easily, either as a result of inflammation or damage. Conditions such as lichen planus pigmentosus (characterised by brown or grey colouring) are rather commonly present in these types of skin, as they are darker in tone.
Steps for protection and prevention
Regardless of your skin type, it is essential to protect your skin from UV radiation. Get used to using sunscreen that provides broad-spectrum coverage with an SPF of 30 or above. Use sunscreen between breaks in case you spend more time in the sun. Put on hats and other protective clothing, which serve as physical barriers, as they may protect the skin against damage caused by UV radiation.
