loss of cohesion between keratinocytes caused by the breakdown of intercellular bridges.
vascular reaction involving the deep dermis or subcutis and consisting of edema manifested as giant wheals and caused by dilation and increased permeability of capillaries (deeper version of urticaria).
Blister (vesicle or bulla)
localized collection of fluid usually in or beneath the epidermis. Bulla: large blister (≥1.0 cm).
Carcinoma in situ
a malignant neoplasm of epithelial origin that has not invaded through the basement membrane.
an acute bacterial infection of the dermis and subcutis that spreads to surrounding soft tissues and is characterized by erythema, warmth, swelling, and pain. The source of the infection is most often a penetrating wound in the area of infection. Cellulitis can also cause fever and enlarged lymph nodes.
Comedo (pl., comedones)
plug of follicular stratum corneum and dried sebum in a hair follicle that leads to follicular distention.
small molecular weight protein molecules (generally <30 kD) that are mediators of inflammation and growth.
infection of the stratum corneum of the epidermis, hair, or claws with fungi of the genera Microsporum, Epidermophyton, or Trichophyton.
abnormal development;; term may be used in association with a congenital or inherited developmental anomaly or in association with an abnormality in maturation of cells within a tissue.
degeneration of dermal connective tissue leading to accumulation of elastotic fibers;; sometimes seen with solar dermatitis
having a predilection to enter the epidermis or other epithelial structures as seen with cutaneous T cell lymphoma (mycosis fungoides).
circumscribed, painful nodule (accumulation of pus) in the dermis secondary to follicular rupture
rupture of follicles usually caused by inflammation, distention, and/or trauma leading to entry of follicular contents into the dermis.
a localized, tumor-like malformation of mature cells and tissues that includes normal components of the organ in which the hamartoma arises but that is disorganized, present in excess, and sometimes larger than normal. Usually, one tissue element predominates (e.g., follicular hamartoma, vascular hamartoma). A hamartoma is not a true neoplasm because it involves the proliferation of more than one cell type and often includes the development of complex structures such as arteries or follicles
congenital skin disorder in which the skin is thickened by scales (hyperkeratosis) that can crack into plates resembling fish scales
slow growing, a term applied to persistent ulcers on the lips of cats, and sometimes incorrectly called "rodent ulcer," a term from the human literature used to refer to ulcerated basal cell carcinoma
inflammation arranged in a layer close to and often obscuring the epidermal-dermal junction (interface), and with vacuolated (hydropic degeneration) and sometimes apoptotic basal cells;; the inflammation can be mild (cell poor) or extensive (cell rich)
dermatitis that develops because of friction between apposing skin surfaces (e.g., adjacent folds)
the epidermal cells that synthesize keratin and comprise more than 90% of epidermal cells
confusing term that generally refers to a dense zone of dermal inflammation parallel to the epidermis usually without basal cell injury
the conventional term for uncommon to rare, often idiopathic, single or grouped papules, plaques, or papillomatous foci covered by scale, and histologically composed of epidermal hyperplasia, lichenoid lymphoplasmacytic dermal inflammation, hyperkeratosis, and parakeratosis. The term dermatitis is probably better than dermatosis as inflammation is present in these lesions
the dark granular pigment produced by melanocytes that is responsible for the brown coloration of hair, skin, and other tissues such as the iris and choroid of the eye
glycosaminoglycan (GAG), a normal component of the intercellular ground substance of the dermis, consists of protein bound to hyaluronic acid
a slowly progressive infection of the cutaneous and subcutaneous tissue, fascia, and sometimes underlying bone caused by traumatic implantation of actinomycetes (actinomycotic mycetoma) or fungi (eumycotic mycetoma)
an acute serious life-threatening subtype of cellulitis usually caused by streptococcal bacterial infection and toxin production, and located within the subcutaneous fat and fascial planes. The clinical lesions are painful, hot, and swollen areas with extensive exudation and necrosis. The condition can progress rapidly and result in systemic shock
circumscribed malformation of the skin assumed to be of congenital or inherited origin, and consisting of any component of the skin. The term "hamartoma" is preferred to nevus to avoid confusion with the pigmented nevus (mole) that arises in the skin of humans
a localized intraepidermal collection of neoplastic lymphocytes characteristic of epitheliotropic lymphoma (mycosis fungoides)
mycotic disease caused by pigmented fungi (dematiaceous fungi) of a variety of genera and species that do not form sclerotic bodies or granules
melanin pigment within dermal macrophages or free in the dermis developing via injury to pigment containing basal layer cells
a flat-topped, solid elevation in the skin that occupies a relatively large surface area in comparison with its height (≥1 cm).
a term used in human medicine to define an ulcerative basal cell carcinoma; sometimes used inappropriately in veterinary medicine to refer to an indolent ulcer affecting the lip of cats.
nonspecific term for clinical signs of scaling, crusting, and greasiness. Primary seborrhea is a more specific term applied to inherited cornification disorders
intercellular edema, which, by widening of the intercellular space and stretching of the "intercellular bridges," creates a sponge-like appearance to the epidermis
usually transient vascular reaction in the upper dermis consisting of edema manifested clinically as wheals (hives);; a more superficial version of angioedema