Antibodies directed against Dsg 1 and plakoglobin. Flaccid vesicles arise on an erythematous base. Erythema, crusting and oozing are seen. Vesicles rupture easily and leave shallow erosions due to their superficial location. Lesions start on the face, neck, upper trunk and may involve most of the body. In advanced stages few vesicles are seen and the appearance is of an exfoliative dermatitis. No oral lesions occur and no extracutaneous signs are noted. Association with other diseases is not found.

Cats Mammary, perinipple, and nail beds are frequently involved. Lymphadenopathy, lameness, pyrexia, pruritus, depression and pitting edema may be seen.

It occurs in certain regions of Brazil, Colombia and Tunisia. Antibodies are directed against Dsg l, Dsc 1,2,3. Affects young people, 60% before 30 years of age, in rural areas (4.7 times higher incidence). The initiating event leading to antibody production has not been determined. A virus transmitted by Simulium spp. bites has been hypothesized to play a role. Intraepidermal blisters spontaneously develop on face and scalp and generalization occurs in most cases.

Environmental and seasonality risk factors for PF were examined in animals and no significant association was found.

Pemphigus vulgaris is considered the most common type of pemphigus in man. In people there is not any sex predilection. The age of onset varies from 50 to 60 years. Pemphigus vulgaris is more common in Jewish and Mediterranean people of HLA DRw4 and DRw6 phenotypes. Antibodies directed against Dsg 3 (130 kD) and plakoglobin (85 kD). Flaccid, non inflammatory vesicles arise form normal appearing skin. These lesions tend to coalesce and rupture easily resulting in large ulcerated areas. Lesions usually appear first on mucosal surfaces, particularly in oral cavity.

Antibodies are directed against Dsg 3. Rare in domestic animals. Reported in dogs and cats. Erythematous macules evolve to vesicles and non healing ulcers. Oral cavity is affected in 90% of cases (palate as well as tongue). Rectal, nasal, nail bed and genital lesions are also seen. Axillae and groin are severely affected.

Disease with a lupus distribution. Lesions are found on sun exposed areas. Antinuclear antibody test (ANA) may be positive.

Variant of PF, restricted to the head. It is considered a cross-over syndrome between PF and lupus erythematosus. Dogs with PE can have positive ANA. Lesions include erythema, crusting and scaling. Nasal depigmentation is common. Patients are otherwise healthy.

Considered as a variant of PV. Antibodies are directed against Dsg 3. Groups of pustules evolve into papillomatous lesions and verrucous vegetative masses. No bullae occur the course of the disease is benign. Oral lesions occur in both type of pemphigus vegetans, tongue lesions are characteristic.

Extremely rare. Animals are not systemically ill. Pustules evolving into papillomatous proliferations are present in intertriginous areas. Some cases previously diagnosed as pemphigus vegetans now appear to have been deep forms of PF and PE. The name panepidermal pustular pemphigus has been proposed for canine pemphigus vegetans and erythematosus.¹

Antibodies are directed against Dsg 3. This is the most aggressive type of pemphigus vegetans. Clinical course is similar to PV. Bullae are the primary lesions, prognosis is guarded. This type of pemphigus differs from PV in that areas will heal with papillomatous ulcerations

Not reported

Humans

Dogs

P. Vulgaris

Intraepidermal suprabasal vesicles with acantholytic cells that may extend to the outer root sheath of the hair. Basal cells remain attached to the basement membrane like a ìrow of tombstonesî. Fully developed vesicles contain clusters of epithelial cells that have lost coherence with their neighboring cells (acantholytic cells).

P. Foliaceous (sporadic and endemic)

Acantholysis precedes neutrophilic exocytosis. Acantholysis occurs below the stratum corneum and in the granular layer.

Neutrophilic exocytosis precede acantholysis, suggesting a different pathogenetic mechanism from the human disease. Spongiosis and acantholysis within stratum spinosum of the epidermis and outer root sheath.

Acantholysis may not be observed in older lesions.

Newmann type Not described

Hallopeau type Suprabasilar acantholysis and Intraepidermic eosinophil abscesses. Papillomatous epidermal hyperplasia and hyperkeratosis. Severe superficial perivascular eosinophilic dermatitis

Hallopeau type Intraepidermal pustules, and acantholysis are seen at all levels of the stratified squamous epithelium and the infundibular outer root sheath. Marked papillated hyperplasia and pustules containing numerous eosinophils are seen.

P. erythematosus

Histopatologic picture is identical with PF. In old lesions hyperkeratosis with acanthosis and dyskeratosis of the granular layer may be evident

Epidermal hyperplasia, subcorneal or intragranular acantholysis with lichenoid cellular infiltrate of lymphocytes, plasma cells, neutrophils and eosinophils. Scattered hydropic basal cells and apoptotic epidermal cells. Pigmentary incontinence may be seen. Acantholytic, dyskeratotic granular epidermal cells (grains) may seen at the surface of erosions

Paraneoplastic P.

Feature of both pemphigus and erythema multiforme are found. Suprabasal acantholysis, dyskeratotic keratinocytes, vacuolar changes of the basilar epidermis.²⁰

Human

Animals

Observations

DIF

Positive test for IgG virtually in all active cases. IgA, IgM and C₃ in 50% of patients. Diffuse intercellular fluorescence is common in all pemphigus types .

Various sensitivities reported in canine by different authors:

Nose and footpad samples give false positives in dogs (IgM); lip samples are more reliable. False negatives may also be due to previous glucocorticoid therapy, improper pH of the Michelís fixative or failure to sample a primary lesion. Since immunoglobulin deposition may be the result of tissue damage, false positives have been reported in dogs with epitheliotropic lymphoma, demodicosis, sarcoptic mange and dermatomycosis. .

IP

Reported sensitivity for canine pemphigus varies among 59% 100%

Formalin fixed samples can be used for both histopathology and IP. Immunosuppressive therapy may induce false negatives. Better results than DIF for pemphigus foliaceus.(still you can have false positives)

IIF

Positive IgG test 80-85%. Early, localized cases or when remission occurs may be negative. Indirect IF is less sensitive than DIF. Circulating antibodies are always of the IgG class. Positive correlation between titers and activity and extent of the disease exists.

In veterinary medicine this tests is not considered a sensitive nor specific test. When detected, titers are usually low. Dogs rarely have high titers of circulating antibodies; sensitivity is variable (0 to 64.3% positive results). Insensitive in the cat and unreliable in the horse. Antibodies in serum are not species specific and canine squamous epithelium is an excellent substrate for human antibodies.

Pemphigus-like antibodies have been reported in dogs with demodicosis.