Desquamation

Source: Wikipedia, the free encyclopedia.
This article is about the medical condition. For the meaning in material sciences, see
Onion-skin weathering
.
Desquamation
Other namesSkin peeling
SpecialtyDermatology

Desquamation occurs when the outermost layer of a tissue, such as the

Latin desquamare 'to scrape the scales off a fish
'.

Physiologic desquamation

Keratinocytes are the predominant cells of the epidermis, the outermost layer of the skin. Living keratinocytes reside in the basal, spinous, or granular layers of the epidermis. The outermost layer of the epidermis is called the stratum corneum and it is composed of terminally differentiated keratinocytes, the corneocytes. In the absence of disease, desquamation occurs when corneocytes are individually shed unnoticeably from the surface of the skin.[1] Typically the time it takes for a corneocyte to be formed and then shed is about 14 weeks but this time can vary depending on the anatomical location that the skin is covering. For example, desquamation occurs more slowly at acral (palm and sole) surfaces and more rapidly where the skin is thin, such as the eyelids. Normal desquamation can be visualized by immersing skin in warm or hot water. This induces the outermost layer of corneocytes to shed, such as is the case after a hot shower or bath.[citation needed]

Corneocytes are held together by corneodesmosomes. In order for desquamation to occur these corneodesmosome connections must be degraded.

SPINK9 and the cysteine protease inhibitors CSTA and CST3.[2] Slowing the process of corneocyte desquamation allows acral (palm and sole) skin to form a thick protective stratum corneum.[2]

Abnormal desquamation

Scale forms on the skin surface in various disease settings, and is the result of abnormal desquamation. In pathologic desquamation, such as that seen in X-linked ichthyosis, 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, which forms visible scales.

bacterial infection such as Staphylococcus aureus,[3] can cause severe desquamation; so can mercury poisoning. Other serious skin diseases involving extreme desquamation include Stevens–Johnson syndrome and toxic epidermal necrolysis (TEN).[4] Radiation can cause dry or moist desquamation.[5] Desquamation is also abnormal in patients with immune-mediated skin diseases such as psoriasis and atopic dermatitis.[2] Abnormal desquamation often results in scale formation on the skin's surface.[2] Lipid composition alterations in scale have been used to construct diagnostic models for human skin disease.[2]

  • Desquamation of skin on hands, caused by scarlet fever infection
    Desquamation of skin on hands, caused by scarlet fever infection
  • Desquamation of skin on fingertips, caused by scarlet fever
    Desquamation of skin on fingertips, caused by scarlet fever
  • Desquamation of skin on the finger, caused by the popping of an acute paronychia
    Desquamation of skin on the finger, caused by the popping of an acute paronychia

Eyes

Certain eye tissues, including the

lens impossible.[7]

See also

References

  1. ^
    PMID 8460510
    .
  2. ^
    PMID 35900871
    .
  3. PMID 10627489
    .
  4. ^ Parillo, Steven J; Parillo, Catherine V. (2010-05-25). "Stevens-Johnson Syndrome". eMedicine. Medcape. Retrieved 2010-09-06.
  5. ^ Centers for Disease Control and Prevention (2005-06-30). "Cutaneous Radiation Injury". CDC. Retrieved 2011-05-15.
  6. ^ Gilbard, Jeffrey P. (November 1, 2003). "Dry Eye: Natural History, Diagnosis and Treatment". Wolters Kluwer Pharma Solutions. Archived from the original on January 30, 2013. Retrieved February 3, 2012.
  7. PMID 18231610
    .

External links

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