Dermatophytosis cytology dog
Clinical Knowledge Insight created by Andrew Lowe, DVM, MSc, DACVD
Dermatophyte test medium (DTM) (right) and enhanced sporulation agar (left) are innoculated with plucked hair and scale. Positive culture shows color change and buff - colored colonies in the DTM (right) after 8 days of incubation. Color change occurred within 24 hrs. of colony growth. Positive culture demonstrates color change and buff - colored colonies in the DTM after 14 days of incubation. Color change occurred within 24 hrs. of colony growth. Macroconidia of M. canis from a positive culture. Note that each spore has more than 6 divisions. Macroconidia of M. gypseum from a positive culture. Note that each spore has 6 or fewer divisions. Microconidia of T. mentagrophytes from a positive culture. Feline patient with multifocal alopecia, erythema and scale due to M. canis infection. Positive Wood's light examination in a feline patient with multi focal alopecia and scale due to M. canis. Note blue/green color change associated with the hair shafts. Canine patient with nodular dermatophytosis ("kerion") lesion due to T. mentagrophytes infection. Canine patient with alopecia, erythema, and crusting due to T. mentagrophytes infection mimicking pemphigus foliaceus. Canine patient with alopecia, erythema, and crusting due to T. mentagrophytes infection. Canine patient with alopecia, erythema, and crusting due to T. mentagrophytes infection. Canine patient with single-limb alopecia, erythema, and crusting due to T. mentagrophytes infection.
ENVIRONMENTAL CONTROL
A discrete swelling containing purulent material, typically in the subcutis Perianal abscess in a dog Absence of hair from areas where it is normally present; may be due to folliculitis, abnormal follicle cycling, or self-trauma Extensive alopecia secondary to cutaneous epitheliotropic lymphoma well-circumscribed, circular, patchy to coalescing alopecia, often associated with folliculitis Moth-eaten alopecia secondary to superficial bacterial folliculitis Regional subcutaneous edema Angioedema due to cutaneous drug eruption Ring-like arrangement of lesions Annular lesions in a dog with erythema multiforme Thinning of the skin or other tissues Cutaneous atrophy due to glucocorticoids Fluid-filled elevation of epidermis, >1cm Bullae in a dog with bullous pemphigoid Blood-filled elevation of epidermis, >1cm Interdigital hemorrhagic bulla in a dog with deep pyoderma and furunculosis dilated hair follicle filled with keratin, sebum Comedones on the ventral abdomen of a dog with hypercortisolism Dried exudate and keratinous debris on skin surface Multifocal crusts due to pemphigus foliaceus Nodule that is epithelial-lined and contains fluid or solid material. Epidermal inclusion cyst Extensive loss of pigment Depigmentation of planum nasale in dog with vitiligo. Patches due to hemorrhage >1cm Ecchymoses of a dogs leg due to vasculitis Circular scale or crust with erythema, associated with folliculitis or ruptured pustules or vesicles Epidermal collarettes in a dog with Staphylococcus superficial bacterial folliculitis Defect in epidermis that does not penetrate basement membrane. Histopathology may be needed to differentiate from ulcer. Erosions in a dog with vasculitis Red appearance of skin due to inflammation, capillary congestion Erythema in a dog with cutaneous drug eruption Thick crust often related to necrosis, trauma, or thermal/chemical burn Eschar from physical trauma Erosions and/or ulcerations due to self-trauma Excoriations in a cat with atopic dermatitis Excessive stratum corneum, confirmed via histopathology. This term is often used to describe the nasal planum and footpads. Fissures of the footpads in a dog with superficial necrolytic dermatitis Ulcer on skin surface that originates from and is contiguous with tracts extending into deeper, typically subcutaneous tissues Perianal fistulas in a dog Accumulation of scale adherent to hair shaft Follicular casts surrounding hairs from a dog with hypothyroidism Excessive stratum corneum, confirmed via histopathology. This term is often used to describe the nasal planum and footpads. Idiopathic hyperkeratosis of the nasal planum (left) and footpads (right) Increased melanin in skin, often secondary to inflammation Inflammatory lesions (left) resulting in post-inflammatory hyperpigmentation (right) Partial pigment loss Idiopathic hypopigmentation of planum nasale Lack of hair due to genetic factors or defects in embryogenesis. Congenital hypotrichosis in chocolate Labrador puppies. Lack of cutaneous pigment Macular leukoderma in a dog Loss of hair pigment Progressive leukotrichia in patient with vitiligo. Thickening of the epidermis, often due to chronic inflammation resulting in exaggerated texture Lichenification of skin in a dog with chronic atopic dermatitis and Malassezia dermatitis Flat lesion associated with color change <1cm Pigmented macule (left) Erythematous macule (right) Increased melanin in skin, may be secondary to inflammation. Post inflammatory hyperpigmentation of this dogs thigh Multifocal, papular, crusting dermatitis; a descriptive term, not a diagnosis Miliary dermatitis in a flea allergic cat A erythematous, macular, papular rash; the erythematous macules are typically 2-10 mm in diameter with coalescence to form larger lesions in some areas Morbiliform eruptions in a dog with a cutaneous drug reaction A solid elevation >1cm Nodules on nose of dog with cutaneous histiocytosis. Abnormal nail morphology due to nail bed infection, inflammation, or trauma; may include: Onychogryphosis, Onychomadesis, Onychorrhexis, Onychoschizia Onychodystrophy in dog with chronic allergies Abnormal claw curvature; secondary to nail bed inflammation or trauma Onychogryphosis in a dog with symmetric lupoid onychodystrophy Claw sloughing due to nail bed inflammation or trauma Onychomadesis in a dog with symmetric lupoid onychodystrophy Claw fragmentation due to nail bed inflammation or trauma Onychorrhexis in a dog with symmetric lupoid onychodystrophy Claw splitting due to nail bed inflammation or trauma Onychoschizia in a dog with symmetric lupoid onychodystrophy Solid elevation in skin 1cm Papules on a dog with superficial bacterial folliculitis Solid elevation in skin 1cm Papules on a dog with superficial bacterial folliculitis Inflammation of the nail fold Paronychia in a dog with symmetric lupoid onychodystrophy Flat lesion associated with color change >1cm Hypopigmented patch (left), erythematous patch (right) Small erythematous or violaceous lesions due to dermal bleeding Petechiae in a dog with cutaneous vasculitis Venous dilation; most commonly associated with hypercortisolism Phlebectasia and cutaneous atrophy due to hypercortisolism in a dog Flat-topped elevation >1cm formed of coalescing papules or dermal infiltration Plaques in a cat with cutaneous lymphoma Raised epidermal infiltration of pus Pustules on the abdomen of a dog with superficial staphylococcal pyoderma. Net-like arrangement of lesions Reticulated leukotrichia on the back of a horse Accumulation of loose fragments of stratum corneum Loose, large scales due to ichthyosis in a Golden Retriever Fibrous tissue replacing damaged cutaneous and/or subcutaneous tissues Scarring (right) following the healing of an ulcer (left) in a dog with sterile nodular dermatitis Undulating, serpentine (snake-like) arrangement of lesions Serpiginous urticarial lesions on a horse Permanent enlargement of vessels resulting in a red or violet lesion (rare) Telangiectasia in a dog with angiomatosis A defect in epidermis that penetrates the basement membrane. Histopathology may be needed to differentiate from an erosion. Ulcerations of the skin of a dog with vasculitis. Wheals (steep-walled, circumscribed elevation in the skin due to edema ) due to hypersensitivity reaction Urticaria in a horse Fluid-filled elevation of epidermis, <1cm Vesicles and bullae on ear pinna due to bullous pemphigoid Steep-walled, circumscribed elevation in the skin due to edema Wheals associated with intradermal allergy testing in a horse |