Parasitic skin infections - Pathology
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Flea Dermatosis
Fly Dermatosis
Myiasis
Helminths
Habronemiasis, Cutaneous
Hookworm Dermatosis
Onchocerciasis
Stephanofilariasis
Lice
Mites
Cheyletiellosis
Chorioptic Mange
Demodicosis
Notoedric mites
Otodectic Dermatosis
Psoroptic Mange
Scabies
Trombiculidiasis
Protozoa
- Cutaneous infection may become a part of systemic infection
- Mostly caused by Leishmania
- Transmitted by sandflies
- Occurs in dogs, cats and rodents (also humans)
- Grossly in dog:
- Generalised alopecia
- Silvery white scales
- Nodules and ulcers if more severe
- Mainly on muzzle, ears and eyes where flies feed
- Microscopically:
- Hyperkeratosis, parakeratosis, crusts
- Granulomatous nodules in dermis
- Macrophages, some lymphocytes and plasma cells - periadnexal pattern, may affect sebaceous glands
- Organisms may be found extra or intracellularly
Ticks
- Local reaction depends on host hypersensitivity and tick's secretions
- Grossly:
- Focal erosions, erythema, crusted ulcers, sometimes alopecia and nodules
- Microscopically:
- Epidermal and dermal necrosis
- Perivascular of diffuse inflammation and necrotic margins
- Eosinophils, macrophages and lymphocytes in exudate
- May form granulomas containing collagenous fibres and lymphoid follicles within dermis