寄生性皮膚疾患 : 猫ニキビダニ症
Helen Power（DVM、DACVD）による臨床知識の理解
- 皮膚片利共生ダニDemodex catiのまれな過剰増殖は一般に、基礎疾患の免疫抑制性疾患または代謝性疾患に関連して起こる。
- 感染性そう痒性ニキビダニDemodex gatoi
どのような疾患か？
Self induced
alopecia due to Demodex gatoi
Self induced
alopecia, forelegs, due to Demodex gatoi
Demodex gatoi adult
- Demodex cati: 脱毛, 落屑, 紅斑性病変, 頭に最もよくみられる, 耳垢性耳炎
- Demodex gatoi:: 腹、前肢、臀部の自己誘発性脱毛
要約
ほかに似ている疾患はあるか？
- 自傷に伴うアレルギー性皮膚疾患
- 耳外部寄生虫
- 皮膚糸状菌症
- 過剰グルーミングおよび自己誘発性の脱毛をもたらす他のそう痒性皮膚疾患：ノミアレルギー、食物アレルギー、アトピー性皮膚炎との鑑別は困難
どのような疾患か？
どのように診断するか？
- きわめてまれであり、免疫抑制性疾患または代謝性疾患や免疫調節療法に関連する頻度がきわめて高い。
- 主な臨床特性はそう痒であり、自己誘発性の腹部脱毛をもたらす。
- 接触感染性
- 唯一の有効な治療法は外用石灰硫黄合剤である。
- 除外診断は外用石灰硫黄合剤に対する反応により下される。
- Miller, WH, Griffin CE, Campbell KL (eds): Small Animal Dermatology, 7th ed, St Louis, Saunders, an imprint of Elsevier 2013 pp 304 -315.
- Morris DO, Beale KM: Feline Demodicosis. In Bonagura JD (ed): Kirk's Current Veterinary Therapy VIII. Philadelphia, W. B. Saunders. 2000 pp 580-582
どのように管理するか？
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 dog’s 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 dog’s 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
