Pemphigus vulgaris most commonly presents with oral blisters (buccal and palatine mucosa, especially), but also includes cutaneous blisters. Other mucosal surfaces, the conjunctiva, nose, esophagus, penis, vulva, vagina, cervix, and anus, may also be affected. Flaccid blisters over the skin are frequently seen with sparing of the skin covering the palms and soles.

Blisters commonly erode and leave ulcerated lesions and erosions. A positive Nikolsky sign (induction of blistering in normal skin or at the edge of a blister) is indicative of the disease.

Severe pain with chewing can lead to weight loss and malnutrition.

There are several types of pemphigus which vary in severity: pemphigus vulgaris, pemphigus foliaceus, Intraepidermal neutrophilic IgA dermatosis, and paraneoplastic pemphigus.

- Pemphigus vulgaris (PV - ICD-10 L10.0) is the most common form of the disorder and occurs when antibodies attack "Desmoglein 3". Sores often originate in the mouth, making eating difficult and uncomfortable. Although pemphigus vulgaris may occur at any age, it is most common among people between the ages of 40 and 60. It is more frequent among Ashkenazi Jews. Rarely, it is associated with myasthenia gravis. Nail disease may be the only finding and has prognostic value in management.

- Pemphigus foliaceus (PF) is the least severe of the three varieties. "Desmoglein 1", the protein that is destroyed by the autoantibody, is found in only the top dry layer of the skin. PF is characterized by crusty sores that often begin on the scalp, and may move to the chest, back, and face. Mouth sores do not occur. This form is also frequent among Ashkenazi Jews. It is not as painful as pemphigus vulgaris, and is often mis-diagnosed as dermatitis or eczema

- Intraepidermal neutrophilic IgA dermatosis is characterized histologically by intraepidermal bullae with neutrophils, some eosinophils, and acantholysis.

- The least common and most severe type of pemphigus is paraneoplastic pemphigus (PNP). This disorder is a complication of cancer, usually lymphoma and Castleman's disease. It may precede the diagnosis of the tumor. Painful sores appear on the mouth, lips, and the esophagus. In this variety of pemphigus, the disease process often involves the lungs, causing bronchiolitis obliterans (constrictive bronchiolitis). Though much less frequent, it is still found the most in the Ashkenazi Jewish population. Complete removal of and/or cure of the tumor may improve the skin disease, but lung damage is generally irreversible.

- Endemic pemphigus foliaceus, including the Fogo Selvagem, the new variant of endemic pemphigus folaiceus in El Bagre, Colombia, South America, and the Tunisian endemic pemphigus in North Africa.

Note that Hailey-Hailey disease, also called familial benign pemphigus, is an inherited (genetic) skin disease, not an autoimmune disease. It is therefore not considered part of the Pemphigus group of diseases.

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. Desmoglein forms the "glue" that attaches adjacent epidermal cells via attachment points called desmosomes. When autoantibodies attack desmogleins, the cells become separated from each other and the epidermis becomes "unglued", a phenomenon called acantholysis. This causes blisters that slough off and turn into sores. In some cases, these blisters can cover a significant area of the skin.

Originally, the cause of this disease was unknown, and "pemphigus" was used to refer to any blistering disease of the skin and mucosa. In 1964, researchers found that the blood of patients with pemphigus contained antibodies to the layers of skin that separate to form the blisters. In 1971, an article investigating the autoimmune nature of this disease was published.

Pemphigus vulgaris is a rare chronic blistering skin disease and the most common form of pemphigus. It is classified as a type II hypersensitivity reaction in which antibodies are formed against desmosomes, components of the skin that function to keep certain layers of skin bound to each other. As desmosomes are attacked, the layers of skin separate and the clinical picture resembles a blister. Over time the condition inevitably progresses without treatment: lesions increase in size and distribution throughout the body, behaving physiologically like a severe burn.

Before the advent of modern treatments, mortality for the disease was close to 90%. Today, the mortality rate with treatment is between 5-15%.

Pemphigus foliaceus is an autoimmune blistering disease of the skin with characteristic lesions that are scaly, crusted erosions, often on an erythematous base. Mucosal involvement is absent even with widespread disease.

If there is an autoimmune IgG buildup in the epidermis, then nearly all of the antibodies 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.

- 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.

The forms of pemphigoid are considered to be connective tissue autoimmune skin diseases. There are several types:

- Gestational pemphigoid or Pemphigoid gestationis (PG) (formerly called Herpes gestationis)

- Bullous pemphigoid (BP) Rarely affect the mouth

- Mucous membrane pemphigoid, also known as Cicatricial pemphigoid (CP) (No skin involvement)

Bullous and Cicatricial pemphigoids usually affect persons who are over age 60. Gestational pemphigoid occurs during pregnancy, typically in the second or third trimester, and/or immediately following pregnancy.

Clinically, the earliest lesions may appear urticarial (like hives), but could also appear dermatitic, targetoid, lichenoid, nodular, or even without visible rash (essential pruritus). Tense bullae eventually erupt, most commonly at the inner thighs and upper arms, but the trunk and extremities are frequently both involved. Any part of the skin surface can be involved. Oral lesions are present in a minority of cases. The disease may be acute, but typically will wax and wane. Several other skin diseases may have similar symptoms. However, milia are more common with epidermolysis bullosa acquisita, because of the deeper antigenic targets. A more ring-like configuration, with a central depression or centrally collapsed bullae may indicate linear IgA disease. Nikolsky's sign is negative unlike pemphigus vulgaris where it is positive.

Pemphigoid is a group of rare autoimmune blistering skin diseases. As its name indicates, pemphigoid is similar in general appearance to pemphigus, but, unlike pemphigus, pemphigoid does not feature acantholysis, a loss of connections between skin cells.

Pemphigoid is more common than pemphigus, and is slightly more common in women than in men. It is also more common in people over 60 years of age than it is in younger people.

Although lichen planus can present with a variety of lesions, the most common presentation is as a well defined area of purple-coloured, itchy, flat-topped papules with interspersed lacy white lines (Wickham's striae). This description is known as the characteristic "6 Ps" of lichen planus: planar (flat-topped), purple, polygonal, pruritic, papules, and plaques. This rash, after regressing, is likely to leave an area of hyperpigmentation that slowly fades. That said, a variety of other lesions can also occur.

Lichen planus may be categorized as affecting mucosal or cutaneous surfaces.

- "Cutaneous" forms are those affecting the skin, scalp, and nails.

- "Mucosal" forms are those affecting the lining of the gastrointestinal tract (mouth, pharynx, esophagus, stomach, anus), larynx, and other mucosal surfaces including the genitals, peritoneum, ears, nose, bladder and conjunctiva of the eyes.

The autoimmune reaction most commonly affects the mouth, causing lesions in the gingiva or gums, but it can also affect areas of mucous membrane elsewhere in the body, such as the sinuses, genitals and anus. When the cornea of the eye is affected, repeated scarring may result in blindness.

"Localized cicatricial pemphigoid" (also known as "Brunsting–Perry cicatricial pemphigoid") refers to a localised variant of cutaneous cicatricial pemphigoid involving the head and the neck without mucosal involvement.

Nikolsky's sign (gentle lateral pressure) on unaffected mucosa or skin raises a bulla. If no lesions are present on examination it may be useful way of demonstrating reduced epithelial adhesion. In contrast, in Pemphigus, the epithelium tends to disintegrate rather than form a bulla.

Nikolsky's sign is present in case of Pemphigus and Cicatricial Pemphigoid, but not in the case of Bullous Pemphigoid.

While the presence of lesions is the denominator among patients with PNP, the characteristics of the lesions differ. The five clinical presentations of lesions associated with PNP include:

- "Pemphigus-like": Flaccid blister (discrete), crusts over the raw exuding skin lesions

- "Pemphigoid-like": Tense blister(s) on brick red erythema

- "Erythema multiforme-like": Severe polymorphic skin and/or mucous membrane lesions

- "Graft-vs.-host disease-like": Widespread lichenoid eruption with severe mucous membrane involvement

- "Lichen planus-like": Small red flat-topped scaly papules

It is most common that mucous membrane lesions of the oral cavity are presented first. They can involve the oropharynx, nasopharynx, tongue, and vermilion (red portion) of the lips. They are also known to develop in the conjunctiva of the eye, anogenital (perineum) region, and esophagus. Cutaneous lesions tend to follow the onset of mucosal lesions. The blisters often erupt in waves, usually affecting the upper trunk, head, neck, and proximal extremities. Pemphigoid-like lesions are seen more often on the extremities. Lichenoid lesions are more common among children, presenting on the trunk and limbs, ranging from small red scaly papules to extensive violet to brown papules extending to the face and neck. Within the spectrum of lichenoid presentations are wounds that have features of erythema multiforme and graft-vs.-host disease. Scaly lesions on the palms of the hand and soles of the feet have been noted to coincide with the lichenoid lesions. Lesions of varying morphology may present simultaneously and transform from one type to another as the disease progresses.

A vesiculobullous disease is a type of mucocutaneous disease characterized by vesicles and bullae (i.e. blisters). Both vesicles and bullae are fluid-filled lesions, and they are distinguished by size (vesicles being less than 5–10 mm and bulla being larger than 5–10 mm, depending upon which definition is used). In the case of vesiculobullous diseases which are also immune disorders, the term "immunobullous" is sometimes used. Examples of vesiculobullous diseases include:

- "Infectious: (viral)"

- Herpes simplex

- Varicella-Zoster infection

- Hand, foot and mouth disease

- Herpangina

- Measles (Rubeola)

- "Immunobullous:"

- Pemphigus vulgaris

- Pemphigoid

- Dermatitis herpetiformis

- Linear immunoglobulin-A disease (linear IgA disease)

- "Genetic:"

- Epidermolysis bullosa

Some features are as follows:

Bullous pemphigoid is an acute or chronic autoimmune skin disease, involving the formation of blisters, more appropriately known as bullae, at the space between the epidermis and dermis skin layers. It is classified as a type II hypersensitivity reaction, with the formation of anti-hemidesmosome antibodies.

The National Institute of Arthritis and Musculoskeletal and Skin Diseases describes it like this:

"Normally, our immune system 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."

Cicatricial pemphigoid (also known as "Mucous Membrane Pemphigoid", "MMP", "Benign mucosal pemphigoid," "Benign mucous membrane pemphigoid," "Ocular pemphigus," and "Scarring pemphigoid") is a rare chronic autoimmune subepithelial blistering disease characterized by erosive skin lesions of the mucous membranes and skin that results in scarring of at least some sites of involvement.

Cicatricial pemphigoid has been referred to by a variety of designations based largely on its site of involvements, with examples of such terminology including "desquamative gingivitis," "ocular pemphigus," and "benign mucous membrane pemphigoid." However, currently "...such designations are thought to be confusing or somewhat misleading (e.g., pemphigus in this context is a misnomer, and this disorder is hardly benign given the extent of morbidity it can cause)."

Pemphigus vegetans is a localized form of pemphigus vulgaris.

in which there is a localized vegetating papillomatous response. The eroded areas do not heal like usual but form papillomatous growth and vegetation.

Accounts for 1-2% of pemphigus cases and is a relatively benign variant of pemphigus vulgaris.

Two forms are recognized:

- "Pemphigus vegetans of Neumann" is a localized disease of pemphigus vulgaris slightly more extensive than pemphigus vegetans of Hallopeau. This type is more common and characterized by early lesions similar to Pemphigus Vulgaris with large bullae and erosive areas. Healing is through formation of granulation tissue. It is named for the Austrian Dermatologist, Isidor Neumann.

- "Pemphigus vegetans of Hallopeau" is a disease of localized pemphigus vulgaris. It is named for François Henri Hallopeau. This type is less aggressive and has pustules not bullae. These pustules heal by verrucios hyperkeratotic vegetations.

It is characterized by outbreaks of rashes and blisters in the skin, usually in the folds of the skins, but also often over large areas of the body. The painful blisters break and sometimes become infected and raw, with new blisters forming over raw skin in a sometimes seemingly unending cycle of outbreaks.elapidated brick wall appearance

The disease presents with the widespread formation of fluid-filled blisters that are thin walled and easily ruptured and the patient can be positive for Nikolsky's sign. Ritter's Disease of the Newborn is the most severe form of SSSS with similar signs and symptoms. SSSS often includes a widespread painful erythroderma, often involving the face, diaper, and other intertriginous areas. Extensive areas of desquamation might be present. Perioral crusting and fissuring are seen early in the course. Unlike toxic epidermal necrolysis, SSSS spares the mucous membranes. It is most common in children under 6 years, but can be seen in adults who are immunosuppressed or have renal failure.

IgA pemphigus is a subtype of pemphigus with two distinct forms:

- "Subcorneal pustular dermatosis" (also known as Sneddon–Wilkinson disease and pustulosis subcornealis) is skin condition that is a rare, chronic, recurrent, pustular eruption characterized histopathologically by subcorneal pustules that contain abundant neutrophils. This is distinct from and not to be confused with subcorneal pustular dermatosis type of IgA pemphigus. Sneddon's syndrome, also known as Ehrmann-Sneddon syndrome, is also a different syndrome.

- "Intraepidermal neutrophilic IgA dermatosis" is characterized histologically by intraepidermal bullae with neutrophils, some eosinophils, and acantholysis.

While the term pemphigus typically refers to "a rare group of blistering autoimmune diseases" affecting "the skin and mucous membranes", Hailey–Hailey disease is not an autoimmune disorder and there are no autoantibodies. According to Pemphigus Pemphigoid Foundation (IPPF), "familial benign chronic pemphigus, or Hailey-Hailey disease, is a different condition from Pemphigus".

Pemphigus herpetiformis (also known as "Acantholytic herpetiform dermatitis," "Herpetiform pemphigus," "Mixed bullous disease," and "Pemphigus controlled by sulfapyridine") is a cutaneous condition, a clinical variant of pemphigus that combines the clinical features of dermatitis herpetiformis with the immunopathologic features of pemphigus.

Pathophysiology:

Pemphigus Herpetiformis is an IGg mediated autoantibodies that affect the epidermal layer of the skin.

Paraneoplastic pemphigus is an autoimmune disorder stemming from an underlying tumor. It is hypothesized that antigens associated with the tumor trigger an immune response resulting in blistering of the skin and mucous membranes.

While patients with malignant and benign tumors are both at risk, malignancy is associated with high mortality rates (near 90%). Current treatment focuses on general wound healing and administering corticosteroids, which has not demonstrated a high success rate. Recent research developments aim to treat the underlying tumor in order to alleviate the symptoms of PNP.

Acantholysis is the loss of intercellular connections, such as desmosomes, resulting in loss of cohesion between keratinocytes, seen in diseases such as pemphigus vulgaris. It is absent in bullous pemphigoid, making it useful for differential diagnosis.

This histological feature is also seen in herpes simplex infections (HSV 1 and 2) and varicella zoster infections (chicken pox and shingles).

Pemphigus erythematosus (also known as "Senear–Usher syndrome") is simply a localized form of pemphigus foliaceus with features of lupus erythematosus.