Dermatology Flashcards
Blastomyces dermatitidis
Blastomycosis- systemic fungal disease the primarily affects dogs, humans, and cats. It is a dimorphic fungus found in Mississippi, Missouri, and Ohio River valley, and mid-Atlantic states and Canada (Quebec, Manitoba, and Ontario). Infection occurs primarily through inhalation. This is a systemic infection that can cause damage to any organ or system including the central nervous system but the most common clinical signs and physical exam findings include: Depression, anorexia, weight loss, fever, lameness, lymphadenopathy, harsh lunch sounds, draining skin lesions, chorioretinitis, uveitis, and cough.
Definitive diagnosis depends on identification of the organism: round to ovoid yeast measuring 8-25 um. It is pale pink when stained with H & E with a refractile, double-contoured wall. They have single broad-based buds. Treat with systemic antifungal therapy, usually itraconazole.
Bullae
large blister containing serous fluid
Cheyletiella
“walking dandruff” genus of mites that live on the skin surface of dogs, cats, and rabbits
Collagenolytic granuloma (aka eosinophilic or linear granuloma)
usually occurs on the nose, chin, oral cavity, or caudal thighs. The lesions are typically raised and ulcerative or nodular.
Collarette
Characterized by a rim of peeling edges and a circular shape. Remnants fo previous primary lesions (vesicle, ballae, pustule, papule). The onset can be sudden and distribution may be widespread. Lesions are often superficial spreading pyoderma but may also be seen with some immune-mediated skin disease.
Cutaneous lupus
immune-mediated skin diseases in dogs
Cutaneous lymphoma
a disease of older dogs and cats with the most common breeds seen in our practice being Boxers and Golden Retrievers (see Photo 2). Cutaneous lymphoma can be epitheliotropic (usually T lymphocyte in origin in the dog) or non-epitheliotropic (usually B lymphocyte in origin). Sometimes referred to as mycosis fungoides, cutaneous lymphoma can have four presentations-exfoliative (see Photo 4, p. 5S) (the patient presents with erythema and a “peeling” of the skin sometimes resulting in large flakes), plaque (see Photo 5, p. 5S) (presents as nonraised, sometimes spherical shaped inflamed lesions), tumor stage (see Photos 6, 7, p. 5S) (usually varying sizes of erythemic raised, almost plateau-like lesions) and mucocutaneous ulceration/erythema.
Demodex
genus of tiny commensal mites that live in or near hair follicles of mammals
Dermatophytsis
infection of the hair, skin, or nails caused by a dermatophyte, which is most commonly of the Trichophyton genus and less commonly of the Microsporum or Epidermophyton genera
Eosinophilic plaques
Occur most frequently on the abdomen and medial thighs but can appear other places. They appear as single or multiple, raised, red, often ulcerated lesions of varying size (0.5-7 cm). They frequently have a cobblestone appearance and unlike eosinophilic ulcers, these are often pruritic. This condition is histopathologically similar to miliary dermatitis and is usually associated with underlying allergy.
Eosinophilic ulcer (aka indolent ulcer)
Typically occurs on the upper lip and may be unilateral or bilateral. They often have a characteristic central area of yellow to pink tissue with a slightly raised circumferential edge.
Folliculitis
Inflammation or an infection of the hair follicle
Furunculosis
Deep folliculitis resulting in a swollen, painful skin lesion
Macule
Change in surface color, without elevation or depression
Microsporum canis
Ringworm of domestic cats, also 70% of canine infections
Zoonotic. About 50% of strains fluoresce with ultraviolet light (Wood’s lamp). M. canis and M. gypseum can both present with white colony growth with a pH change at 5 to 7 days, but require different management strategies. Ultimate source of M. canis is a potentially asymptomatic cat.
