Pemphigus foliaceus is an
autoimmune blistering disease (
bullous disorder) of the skin. Pemphigus foliaceus causes a characteristic
inflammatory attack at the subcorneal layer of
epidermis
The epidermis is the outermost of the three layers that comprise 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 rele ...
, which results in skin lesions that are scaly or crusted erosions with an
erythematous (red) base.
[Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). Page 558–562. McGraw-Hill. .] Mucosal
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...
involvement is absent even with widespread disease.
If there is an autoimmune
IgG
Immunoglobulin G (Ig G) is a type of antibody. Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in blood circulation. IgG molecules are created and released by plasma B cells. Each IgG a ...
buildup in the
epidermis
The epidermis is the outermost of the three layers that comprise 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 rele ...
, then nearly all of the
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
are aimed against
desmoglein 1. The effect of the antibodies and the immunological pathway is most likely one of three mechanisms:
*
Steric hindrance of the desmoglein 1: The antibody caps off the site for intracellular binding to another
keratinocyte.
* Activation of an
endocytic pathway: The antibody activates a pathway which causes an internalization of desmogleïn 1, which in turn causes a loss of
adhesion
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another).
The forces that cause adhesion and cohesion can be ...
.
* Disruption of function: In this case, the antibody blocks the desmoglein 1 from being formed into a
desmosome. This in turn causes a loss of adhesion with
acantholysis as a result.
Cause
The
National Institute of Arthritis and Musculoskeletal and Skin Diseases describes it like this:
''Normally, our
immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
produces antibodies that attack viruses and harmful bacteria to keep us healthy. In people with pemphigus, however, the immune system mistakenly attacks the cells in the epidermis, or top layer of the skin, and the mucous membranes. The immune system produces antibodies against proteins in the skin known as desmogleins. These proteins form the glue that keeps skin cells attached and the skin intact. When desmogleins are attacked, skin cells separate from each other and fluid can collect between the layers of skin, forming blisters that do not heal. In some cases, these blisters can cover a large area of skin.''
Diagnosis
Pemphigus foliaceus is diagnosed base on history, biopsy of the affected skin, and testing either a blood sample or a skin sample for the antibodies that cause pemphigus.
Treatment
Epidemiology
Pemphigus is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
in the rural areas of Brazil, especially along inland riverbeds.
History
Pierre Louis Alphée Cazenave first described the disease in 1844.
Medscape Reference
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See also
* List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ...
* Pemphigus
Pemphigus ( or ) is a rare group of blistering autoimmune diseases that affect the skin and mucous membranes.
The name is derived from the Greek root ''pemphix'', meaning "pustule".
In pemphigus, autoantibodies form against desmoglein, whi ...
References
External links
Chronic blistering cutaneous conditions
Rare diseases
{{Cutaneous-condition-stub