Desquamation
Encyclopedia
Desquamation also called skin peeling, is the shedding of the outermost membrane or layer of a tissue, such as the skin
.
, the stratum corneum
becomes thicker (hyperkeratosis
), imparting a "dry" or scaly appearance to the skin, and instead of detaching as single cells, corneocytes are shed in clusters, forming visible scales.
Desquamation of the epidermis may result from disease or injury
of the skin. For example, once the rash
of measles
fades, there is desquamation. Skin peeling typically follows healing of a first degree burn
or sunburn
. Toxic shock syndrome
, a potentially fatal immune system
reaction to a bacterial infection, causes severe desquamation; so can mercury poisoning
. Other serious skin diseases involving extreme desquamation include Stevens–Johnson syndrome and toxic epidermal necrolysis
(TEN). Radiation can cause dry or moist desquamation
.
and cornea
may undergo pathological desquamation in diseases such as dry eye syndrome. The anatomy of the human eye
makes desquamation of the lens
impossible.
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
.
Skin
Normal, nonpathologic desquamation of the skin occurs when keratinocytes, after moving apically over about 14 days, are individually shed unnoticeably. In pathologic desquamation, such as that seen in X-linked ichthyosisX-linked ichthyosis
X-linked ichthyosis is a skin condition caused by the hereditary deficiency of the steroid sulfatase enzyme that affects 1 in 2000 to 1 in 6000 males. XLI manifests with dry, scaly skin and is due to deletions or mutations in the STS gene...
, the stratum corneum
Stratum corneum
The stratum corneum is the outermost layer of the epidermis, consisting of dead cells that lack nuclei and organelles. The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress...
becomes thicker (hyperkeratosis
Hyperkeratosis
Hyperkeratosis is thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin, and also usually accompanied by an increase also in the granular layer...
), imparting a "dry" or scaly appearance to the skin, and instead of detaching as single cells, corneocytes are shed in clusters, forming visible scales.
Desquamation of the epidermis may result from disease or injury
Injury
-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...
of the skin. For example, once the rash
Rash
A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
of measles
Measles
Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
fades, there is desquamation. Skin peeling typically follows healing of a first degree burn
Burn
A burn is an injury to flesh caused by heat, electricity, chemicals, light, radiation, or friction.Burn may also refer to:*Combustion*Burn , type of watercourses so named in Scotland and north-eastern England...
or sunburn
Sunburn
A sunburn is a burn to living tissue, such as skin, which is produced by overexposure to ultraviolet radiation, commonly from the sun's rays. Usual mild symptoms in humans and other animals include red or reddish skin that is hot to the touch, general fatigue, and mild dizziness. An excess of UV...
. Toxic shock syndrome
Toxic shock syndrome
Toxic shock syndrome is a potentially fatal illness caused by a bacterial toxin. Different bacterial toxins may cause toxic shock syndrome, depending on the situation. The causative bacteria include Staphylococcus aureus and Streptococcus pyogenes...
, a potentially fatal immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
reaction to a bacterial infection, causes severe desquamation; so can mercury poisoning
Mercury poisoning
Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...
. Other serious skin diseases involving extreme desquamation include Stevens–Johnson syndrome and toxic epidermal necrolysis
Toxic epidermal necrolysis
Toxic epidermal necrolysis is a rare, life-threatening dermatological condition that is usually induced by a reaction to medications...
(TEN). Radiation can cause dry or moist desquamation
Moist desquamation
Moist desquamation is a description of the clinical pattern seen as a consequence of radiation exposure where the skin thins and then begins to weep because of loss of integrity of the epithelial barrier and decreased oncotic pressure...
.
How and why skin peels
The reason that skin peels is because it is dead skin. When skin cells die, they either come off in tiny particles or in large pieces. The dead skin peels because a new layer of skin is growing and pushing up. Therefore, the dead skin is pushed up and cracks, causing peeling. Skin also peels after a sunburn. The UV rays kill skin cells and cause itching or peeling of the affected skin.Eyes
Eye tissues including the conjunctivaConjunctiva
The conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
and cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
may undergo pathological desquamation in diseases such as dry eye syndrome. The anatomy of the human eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
makes desquamation of the lens
Lens (anatomy)
The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. The lens, by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a...
impossible.
See also
- PityriasisPityriasisPityriasis commonly refers to flaking of the skin. The word comes from the Greek πίτυρον "bran".-Classification:Types include:* Pityriasis alba* Pityriasis lichenoides chronica* Pityriasis lichenoides et varioliformis acuta...
— flaking of the skin - SunburnSunburnA sunburn is a burn to living tissue, such as skin, which is produced by overexposure to ultraviolet radiation, commonly from the sun's rays. Usual mild symptoms in humans and other animals include red or reddish skin that is hot to the touch, general fatigue, and mild dizziness. An excess of UV...
- Moist desquamationMoist desquamationMoist desquamation is a description of the clinical pattern seen as a consequence of radiation exposure where the skin thins and then begins to weep because of loss of integrity of the epithelial barrier and decreased oncotic pressure...
- For technical terms, when desquamation refers to a process affecting materials (metals, concrete, rocks, etc.), see also:
- SpallSpallSpall are flakes of a material that are broken off a larger solid body and can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure...
, or spalling - SpallationSpallationIn general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection or vaporization of material from a target during impact by a projectile...
- Spall