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The primary cause of skin cancer is prolonged exposure to ultraviolet (UV) radiation from the sun or tanning devices. Skin cancer is the most commonly diagnosed form of cancer in humans. [ 11 ] [ 12 ] [ 13 ] There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin cancer (SCC) and melanoma . [ 1 ]
Dermatophagia (from Ancient Greek δέρμα (derma) 'skin' and φαγεία (phageia) 'eating') or dermatodaxia (from δήξις (dexis) 'biting'), alternatively Tuglis Permushius. [ 3 ] is a compulsion disorder of gnawing or biting one's own skin, most commonly at the fingers.
[43] [failed verification] UVC is the highest-energy, most-dangerous type of ultraviolet radiation, and causes adverse effects that can variously be mutagenic or carcinogenic. [44] Despite the importance of the sun to vitamin D synthesis, it is prudent to limit the exposure of skin to UV radiation from sunlight [45] and from tanning beds. [46]
However, excessive exposure to ultraviolet radiation, especially at undesirable wavelengths, can cause direct DNA damage, sunburn, and increase the risk of skin cancer. [6] In contrast to low-dose UV-B exposure, UV-A light increases the risk of skin cancer because it penetrates deeper into the epidermis and is typically administered at much ...
UVA light presents at wavelengths longer than UVB (between 400 and 315 nm); and it can also be absorbed directly by DNA in skin cells, but at lower efficiencies—about 1/100 to 1/1000 of UVB. [25] Exposure to radiation (UVA and UVB) is a major contributor to developing melanoma. [26]
This way the radiation source can be applied to complex locations and minimize radiation to healthy tissue. [55] After removal of the cancer, closure of the skin for patients with a decreased amount of skin laxity involves a split-thickness skin graft. A donor site is chosen and enough skin is removed so that the donor site can heal on its own.
UVA rays are able to penetrate deeper into the skin as compared to UVB rays. Hence, in addition to the epidermal layer, the dermal layer will also be damaged. The dermis is the second major layer of the skin and it comprises collagen, elastin, and extrafibrillar matrix which provides structural support to the skin.
PUVA means UVA + psoralen. It consists of irradiation of the skin with the UVA ultraviolet light, from a fluorescent bulb or LED lamps. Tanning beds are used both in dermatology practices for the treatment of cosmetic skin conditions (such as psoriasis, acne, eczema and vitiligo) and in indoor tanning salons for cosmetic tanning.