Pemphigus foliaceus is an

autoimmune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". ...

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

erythema Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not asso ...

tous (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 ...

buildup in the

, 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 Desmoglein-1 is a protein that in humans is encoded by the ''DSG1'' gene. Desmoglein-1 is expressed everywhere in the skin epidermis, but mainly it is expressed in the superficial upper layers of the skin epidermis. Function Desmosomes are Cell ...

. The effect of the antibodies and the immunological pathway is most likely one of three mechanisms: *

Steric hindrance Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions ...

of the desmoglein 1: The antibody caps off the site for intracellular binding to another

keratinocyte Keratinocytes are the primary type of Cell (biology), cell found in the epidermis (skin), epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the stratum basale, basal layer (''str ...

. * 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 b ...

. * Disruption of function: In this case, the antibody blocks the desmoglein 1 from being formed into a

desmosome A desmosome (; "binding body"), also known as a macula adherens (plural: maculae adherentes) (Latin for ''adhering spot''), is a cell structure specialized for cell-to-cell adhesion. A type of junctional complex, they are localized spot-like adh ...

. This in turn causes a loss of adhesion with

acantholysis Acantholysis is the loss of intercellular connections, such as desmosomes, resulting in loss of cohesion between keratinocytes,Kumar, Vinay; Fausto, Nelso; Abbas, Abul (2004) ''Robbins & Cotran Pathologic Basis of Disease'' (7th ed.). Saunders. ...

as a result.

Cause

The

National Institute of Arthritis and Musculoskeletal and Skin Diseases The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) is one of the institutes and centers that make up the National Institutes of Health, an agency of the United States Department of Health and Human Services (HHS). ...

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 Pierre Louis Alphée Cazenave (5 May 1795 – 9 April 1877) was a French dermatologist who practiced medicine at the Hôpital Saint-Louis in Paris. In 1823 he was appointed interne to the hospitals of Paris, and in 1835 became ''professor ag ...

first described the disease in 1844.Medscape Reference
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References

External links

Chronic blistering cutaneous conditions Rare diseases {{Cutaneous-condition-stub