Pemphigus foliaceus in a cat

17 Pemphigus foliaceus in a cat


Typically, pemphigus foliaceus presents with a history of crusting skin lesions that most commonly start over the pinnae and face, with later involvement of the trunk and limbs. Paronychia is a common finding in cats. Pruritus may be absent to severe, and many cases show intermittent depression, pyrexia and anorexia. Quite frequently, when questioned, owners may have recognized a waxing and waning of the symptoms over time.

The relevant history in this case was:


Pemphigus foliaceus is currently considered a heterogeneous autoimmune skin disease, resulting from the formation of predominantly IgG1 and IgG4 autoantibodies that target the intercellular spaces of the stratum spinosum and stratum granulosum of the epidermis. The precise target(s) (autoantigens) of these antibodies remain(s) unclear. There have been no studies reporting the nature of the specific autoantigen in cats, but a considerable amount of work has been done in looking for the autoantigen in canine pemphigus foliaceus. It was originally thought that the major autoantigen was desmoglein-1, a component of the desmosomes, which are responsible for keratinocyte–keratinocyte adhesion in the epidermis of the skin and hair follicles, but recent work has shown that this is an antigen of minor importance in canine pemphigus foliaceus, highlighting the heterogeneous nature of this disease.

Pustule formation: The exact mechanism of pustule formation in association with antibody formation is complex and incompletely elucidated. However, antibody binding to desmosomal structures leads to the release of plasminogen by keratinocytes that results in activation of plasmin, a protease that destroys desmosomal structures, leading to acantholysis and the separation of keratinocytes in the stratum spinosum. The clefts thus formed are filled by neutrophils migrating into the epidermis from the circulation to form pustules. Acantholytic keratinocytes, cells that have become detached from the stratum spinosum as a result of the acantholytic process, are also present within the pustules. These cells are nucleated, as opposed to the fully differentiated cells of the stratum corneum that have lost their nuclei. They tend to have a rounded appearance and have basophilic staining characteristics. The cytological finding of acantholytic keratinocytes combined with a neutrophilic infiltrate is consistent with pemphigus foliaceus, but may also be found in cases of bacterial pyoderma and also dermatophytosis, particularly in cases of infection with Trichophyton spp.

Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Pemphigus foliaceus in a cat

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