Bullous pemphigoid may be self-resolving in a period ranging from several months to many years even without treatment. Poor general health related to old age is associated with a poorer prognosis.

In most cases of bullous pemphigoid, no clear precipitating factors are identified. Potential precipitating events that have been reported include exposure to ultraviolet light and radiation therapy. Onset of bullous pemphigoid has also been associated with certain drugs, including furosemide, and other nonsteroidal anti-inflammatory agents, captopril, penicillamine, and antibiotics.

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.

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)."

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.

Vesicular pemphigoid is a cutaneous condition, a clinical variant of bullous pemphigoid, characterized by a dermatitis herpetiformis-like presentation with grouped small tense blisters.

Pemphigus foliaceus has been recognized in pet dogs, cats, and horses and is the most common autoimmune skin disease diagnosed in veterinary medicine. Pemphigus foliaceus in animals produces clusters of small vesicles that quickly evolve into pustules. Pustules may rupture, forming erosions or become crusted. Left untreated, pemphigus foliaceus in animals is life-threatening, leading to not only loss of condition but also secondary infection.

Pemphigus vulgaris is a very rare disorder described in pet dogs and cats. Paraneoplastic pemphigus has been identified in pet dogs.

In contrast to cutaneous LP, which is self limited, lichen planus lesions in the mouth may persist for many years, and tend to be difficult to treat, with relapses being common. Atrophic/erosive lichen planus is associated with a small risk of cancerous transformation, and so people with OLP tend to be monitored closely over time to detect any potential change early. Sometimes OLP can become secondarily infected with Candida organisms.

In 2016, interferon gamma/CXCL10 axis was hypothesized to be a target for treatments that reverse inflammation. Apremilast is undergoing investigation as a potential treatment .

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.

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.

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:

Pathogenically, it is a Type II Hypersensitivity reaction where circulating complement-fixing IgG antibodies bind to an antigen (a 180-kDa protein, BP-180) in the hemidesmosomes (attach basal cells of epidermis to the basal lamina and hence to dermis) of the dermoepidermal junction (DEJ) , leading to blister formation as loss of hemidesmosomes causes the epidermis to separate from dermis. The immune response is even more highly restricted to the NC16A domain. The primary site of autoimmunity seems not to be the skin, but the placenta, as antibodies bind not only to the basement membrane zone of the epidermis, but also to that of chorionic and amniotic epitheli. Aberrant expression of MHC class II molecules on the chorionic villi suggests an allogenic immune reaction to a placental matrix antigen, thought to be of paternal origin .Recently, both IgA22 and IgE24 antibodies to either BP180 or BP230 have also been detected in pemphigoid gestationis.

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%.

Because the eruption is transient and self-limiting, no treatment is indicated.

In many children hydroa vacciniforme (HV) regresses spontaneously by early adulthood. In the 29 patients followed by Iwatuski et al., 11 of the 18 with definite or probable HV were available for follow-up and all were alive without progression of their symptoms. Some had recurrent eruptions of HV. In contrast out of 11 severe patients in this study, 6 had evidence of chronic EBV infection, 5 had hypersensitivity to mosquito bites, 4 had virus-associated hemophagocytic syndrome. 6 of the severe group had natural killer-cell lymphocytosis in the peripheral blood.

The cause of erythema toxicum is thought to be an activation of the immune system. Some neonates are more sensitive than others and develop erythematous spots all over the body. Another theory is hypersensitivity to detergents in bedsheets and clothing is sometimes suspected, but the connection remains unproven.

It is thought to be a benign condition that causes no discomfort to the infant. The rash will generally disappear spontaneously in about 2 weeks.

Pregnant women with PG should be monitored for conditions that may affect the fetus, including, but not limited to, low or decreasing volume of amniotic fluid, preterm labor, and intrauterine growth retardation. Onset of PG in the first or second trimester and presence of blisters may lead to adverse pregnancy outcomes including decreased gestational age at delivery, preterm birth, and low birth weight children. Such pregnancies should be considered high risk and appropriate obstetric care should be provided. Systemic corticosteroid treatment, in contrast, does not substantially affect pregnancy outcomes, and its use for PG in pregnant women is justified. PG typically reoccurs in subsequent pregnancies. Passive transfer of the mother’s antibodies to the fetus causes some (about 10%) newborns to develop mild skin lesions, but these typically will resolve within weeks of parturition.

Vulvar childhood pemphigoid is a cutaneous condition, a childhood form of bullous pemphigoid, peculiar variant with involvement of the genital area and perineum.

As PNP is ultimately caused by the presence of a tumor, it is not contagious. There is no known way to predict who will become afflicted with it. Patients with cancer are therefore a group at risk. Although PNP has been known to affect all age groups, it is more likely to afflict middle-aged to older patients.

Pemphigus is an autoimmune disease caused by antibodies directed against both desmoglein 1 and desmoglein 3 present in desmosomes. Loss of desmosomes results in loss of cohesion between keratinocytes in the epidermis, and a disruption of the barrier function served by intact skin. The process is classified as a type II hypersensitivity reaction (in which antibodies bind to antigens on the body's own tissues). On histology, the basal keratinocytes are usually still attached to the basement membrane leading to a characteristic appearance called "tombstoning." Transudative fluid accumulates in between the keratinocytes and the basal layer (suprabasal split), forming a blister and resulting in what is known as a positive Nikolsky's sign. This is a contrasting feature from bullous pemphigoid, which is thought to be due to anti-hemidesmosome antibodies, and where the detachment occurs between the epidermis and dermis (subepidermal bullae). Clinically, pemphigus vulgaris is characterized by extensive flaccid blisters and mucocutaneous erosions. The severity of the disease, as well as the mucosal lesions, is believed to be directly proportional to the levels of desmoglein 3. Milder forms of pemphigus (like foliacious and erythematoses) are more anti-desmoglein 1 heavy.

The disease arises most often in middle-aged or older people, usually starting with a blister that ruptures easily. It can also start with blisters in the mouth. The lesions can become quite extensive.

Tetter refers to any skin condition characterized by reddish vesicular eruptions and intense itching. Common diseases called tetter include:

- Eczema and Duhring's disease

- Herpes

- Porphyria cutanea tarda (PCT)

- Psoriasis

- Ringworm and jock itch

Urticarial dermatoses are distinct from urticaria, which examples being drug-induced urticaria, eosinophilic cellulitis and bullous pemphigoid. It is important to distinguish urticaria from urticarial dermatoses. The individual wheals of urticaria are ‘here today and gone tomorrow’ (i.e. they last less than 24 hours), whereas with urticarial dermatoses, the individual lesions last for days or longer.

Hailey–Hailey disease, or familial benign chronic pemphigus or familial benign pemphigus, was originally described by the Hailey brothers (Hugh Edward and William Howard) in 1939. It is a genetic disorder that causes blisters to form on the skin.

Many 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 the external environment. The skin weighs an average of four kilograms, covers an area of two square meters, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.

The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum.

The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.

The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source.

Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.