Intrinsic ageing and extrinsic ageing are terms used to describe cutaneous ageing of the skin and other parts of the integumentary system, which while having epidermal concomitants, seems to primarily involve the dermis. [1] Intrinsic ageing is influenced by internal physiological factors alone, and extrinsic ageing by many external factors. Intrinsic ageing is also called chronologic ageing, and extrinsic ageing is most often referred to as photoageing.
The effects of intrinsic ageing are caused primarily by internal factors alone. It is sometimes referred to as chronological ageing and is an inherent degenerative process due to declining physiologic functions and capacities. Such an ageing process may include qualitative and quantitative changes and includes diminished or defective synthesis of collagen and elastin in the dermis.
Extrinsic ageing of skin is a distinctive declination process caused by external factors, which include ultra-violet radiation, cigarette smoking, air pollution, among others. Of all extrinsic causes, radiation from sunlight has the most widespread documentation of its negative effects on the skin. Because of this, extrinsic ageing is often referred to as photoageing. [2] [3] [4] Photoageing may be defined as skin changes caused by chronic exposure to UV light. Photodamage implies changes beyond those associated with ageing alone, defined as cutaneous damage caused by chronic exposure to solar radiation and is associated with emergence of neoplastic lesions.
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
The epidermis is the outermost of the three layers that make up the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of multiple layers of flattened cells that overlie a base layer composed of columnar cells arranged perpendicularly.
Squamous-cell skin cancer, also known as cutaneous squamous-cell carcinoma (cSCC), is one of the main types of skin cancer along with basal cell cancer, and melanoma. It usually presents as a hard lump with a scaly top but can also form an ulcer. Onset is often over months. Squamous-cell skin cancer is more likely to spread to distant areas than basal cell cancer. When confined to the outermost layer of the skin, a precancerous or in situ form of cSCC is known as Bowen's disease.
Panniculitis is a group of diseases whose hallmark is inflammation of subcutaneous adipose tissue. Symptoms include tender skin nodules, and systemic signs such as weight loss and fatigue.
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment.
Actinic keratosis (AK), sometimes called solar keratosis or senile keratosis, is a pre-cancerous area of thick, scaly, or crusty skin. Actinic keratosis is a disorder (-osis) of epidermal keratinocytes that is induced by ultraviolet (UV) light exposure (actin-). These growths are more common in fair-skinned people and those who are frequently in the sun. They are believed to form when skin gets damaged by UV radiation from the sun or indoor tanning beds, usually over the course of decades. Given their pre-cancerous nature, if left untreated, they may turn into a type of skin cancer called squamous cell carcinoma. Untreated lesions have up to a 20% risk of progression to squamous cell carcinoma, so treatment by a dermatologist is recommended.
Mycosis fungoides, also known as Alibert-Bazin syndrome or granuloma fungoides, is the most common form of cutaneous T-cell lymphoma. It generally affects the skin, but may progress internally over time. Symptoms include rash, tumors, skin lesions, and itchy skin.
A radiation burn is a damage to the skin or other biological tissue and organs as an effect of radiation. The radiation types of greatest concern are thermal radiation, radio frequency energy, ultraviolet light and ionizing radiation.
Erythema ab igne (EAI), also known as hot water bottle rash, is a skin condition caused by long-term exposure to heat. Prolonged thermal radiation exposure to the skin can lead to the development of reticulated erythema, hyperpigmentation, scaling and telangiectasias in the affected area. Some people may complain of mild itchiness and a burning sensation, but often, unless a change in pigmentation is seen, it can go unnoticed.
Skin care is the range of practices that support skin integrity, enhance its appearance and relieve skin conditions. They can include nutrition, avoidance of excessive sun exposure and appropriate use of emollients. Practices that enhance appearance include the use of cosmetics, botulinum, exfoliation, fillers, laser resurfacing, microdermabrasion, peels, retinol therapy and ultrasonic skin treatment. Skin care is a routine daily procedure in many settings, such as skin that is either too dry or too moist, and prevention of dermatitis and prevention of skin injuries.
Cheilitis is inflammation of the lips. This inflammation may include the perioral skin, the vermilion border, or the labial mucosa. The skin and the vermilion border are more commonly involved, as the mucosa is less affected by inflammatory and allergic reactions.
The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to most of the other mammals' skin, and it is very similar to pig skin. Though nearly all human skin is covered with hair follicles, it can appear hairless. There are two general types of skin, hairy and glabrous skin (hairless). The adjective cutaneous literally means "of the skin".
Restrictive lung diseases are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation. Pulmonary function test demonstrates a decrease in the forced vital capacity.
Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin condition, characterised by blisters filled with a watery fluid that is intensely itchy. DH is a cutaneous manifestation of Coeliac disease. DH is neither related to nor caused by herpes virus: the name means that it is a skin inflammation having an appearance similar to herpes.
Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include: red or reddish skin that is hot to the touch or painful, general fatigue, and mild dizziness. Excessive UV radiation can be life-threatening in extreme cases. Excessive UV radiation is the leading cause of, primarily, non-malignant skin tumors. Sunburn is an inflammatory response in the tissue triggered by direct DNA damage by UV radiation. When the cells' DNA is overly damaged by UV radiation, type I cell-death is triggered and the tissue is replaced. Sun protective measures including sunscreen and sun protective clothing are widely accepted to prevent sunburn and some types of skin cancer. Special populations, including children, are especially susceptible to sunburn and protective measures should be used to prevent damage.
Cutaneous small-vessel vasculitis (CSVV), also known as hypersensitivity vasculitis, cutaneous leukocytoclastic vasculitis, hypersensitivity angiitis, cutaneous leukocytoclastic angiitis, cutaneous necrotizing vasculitis and cutaneous necrotizing venulitis, is inflammation of small blood vessels, characterized by palpable purpura. It is the most common vasculitis seen in clinical practice.
Photoaging or photoageing is a term used for the characteristic changes to skin induced by chronic UVA and UVB exposure. Tretinoin is the best studied retinoid in the treatment of photoaging
Actinic elastosis, also known as solar elastosis, is an accumulation of abnormal elastin in the dermis of the skin, or in the conjunctiva of the eye, which occurs as a result of the cumulative effects of prolonged and excessive sun exposure, a process known as photoaging.
Tooth discoloration is abnormal tooth color, hue or translucency. External discoloration is accumulation of stains on the tooth surface. Internal discoloration is due to absorption of pigment particles into tooth structure. Sometimes there are several different co-existent factors responsible for discoloration.
Collagen is a protein that is an important part of connective tissues in the body. It is a rigid, non-soluble and fibrous protein that adds up to one third of the proteins found in the human body. Collagen is mostly made up of molecules that are packed together to form long and thin fibrils that support each other and ensure the skin is strong and elastic. There are various types of collagen which have individual roles and structures. Most collagen belongs to types 1, 2 and 3. Collagen consists mainly of amino acids and can be mostly found in tendons, muscles, bones, skin, ligaments and other fibrous tissues. It helps keep the skin strong and supple, and sustains the renewal of skin cells and replacement of damaged and dead body cells. The collagen tissues support the formation of bones, tendons, and cartilage that form depending on the level of mineralization. However, an individual can lose collagen components in the body due to exposure to ultraviolet light, tobacco, excessive intake of sugar, and aging. This loss of collagen can cause the skin to lose elasticity, reduction of the thickness of the epidermis, increase in the formation of wrinkles and sagging, and also make the skin vulnerable and easily damaged.