Miliary dermatitis
From Felipedia
Miliary dermatitis - also known as papulocrustous dermatitis - is a term that is used to describe the appearance on a cat's skin of multiple crusty lesions. The lesions of feline miliary dermatitis are multiple small, crusty bumps with redness underneath. The lesions are sometimes limited to small areas of the body like the base of the tail, or around the neck or head areas. In other cases, the lesions can cover a large portion of the body. Many times the lesions are itchy, sometimes severely so. In these cases, there may be more severe damage to the skin because of the constant scratching and licking by the cat, which in turn, may bring on grooming disorders. Feline miliary dermatitis has been known as "scabby cat disease", "feline eczema" and "blotch". The word "miliary" is used because the lesions look somewhat like millet seeds.
Feline miliary dermatitis is not really a specific disease itself but a set of symptoms which can be caused by a vast number of diseases. As many as 8 out of 10 cases of miliary dermatitis in cats are thought to be the result of flea bite hypersensitivity, but in some cases no underlying cause is identified.
This inflammatory reaction of the skin is common to a wide range of underlying conditions including:
1. Ectoparasites - Notoedres spp, Cheyletiella spp, Otodectes spp, Demodex spp
- usually in cats under 6 months of age, as is seen in canine mange
2. Allergies/Immune-mediated
- - Flea-bite hypersensitivity - flea dirt evident in coat
- - Mosquito-bite hypersensitivity - access to outdoors at dusk and dawn
- - Adverse food reaction - young cats under 3 years old
- - Atopy - generalised skin lesions as well as facial
- - Contact dermatitis - usually oral/perioral lesions; also associated with application of ocular/oral/aural medications
- - Eosinophilic granuloma complex
3. Bacteria & Fungi
- - Cat bite abscess
- - Feline acne
- - Superficial pyoderma (Staphylococcus intermedius, Streptococcal spp, Pseudomonas aeruginosa, Proteus mirabilis, Actinomyces spp), Persians predisposed to bacterial pyoderma and Malassezia spp infection due to brachycephalic syndrome
- - Dermatophytes (Microsporum spp, Trichophyton spp, Malassezia spp, Candida spp)
- - Tuberculosis (mycobacterial infection), Feline Multisystemic Granulomatous Mycobacteriosis, Feline Leprosy
4. Viruses
- - FHV Herpes virus
- - Herpes virus-associated erythema multiforme in cats under 3 years of age; history of URTI
- - Calicivirus infection
- - Papilloma
- - Feline Pox virus infection
- - FeLV
5. Neoplasia
- - Mast cell tumour
- - Epitheliotropic lymphoma - Cutaneous lymphoma can be classified as epitheliotropic (closely conforming to the epidermis) or non-epitheliotropic. The epitheliotropic form is typically of T-cell origin and is also called mycosis fungoides. The non-epitheliotropic form is typically of B-cell origin. This is a rare disease in cats.
- - Feline Sarcoid and/or Fibropapilloma
- - Xanthoma
- - Merkel Cell Tumour (neuroendocrine carcinoma)
- - Melanoma
- - Basal cell tumour
- - Mast cell tumour
- - Dilated Pore of Winer
- - Squamous cell carcinoma, Solar Keratosis/Actinic Dermatitis, Multicentric Squamous Cell Carcinoma In Situ: Bowen's Disease
- - Urticaria pigmentosa - primarily in Devon rex and Sphinx cats
6. Autoimmune
- - Eosinophilic granuloma complex
- - Pemphigus foliaceus
- - Pemphigus erythematosus
- - Discoid Lupus erythematosus
- - Systemic Lupus erythematosus
7. Systemic disease
- - Pancreatic paraneoplastic alopecia - usually a concurrent GI problem exists and poor condition (e.g. weight loss and dehydration).
- - Paraneoplastic exfoliative dermatitis
- - Idiopathic lymphocytic mural folliculitis
8. Miscellaneous
- - Cutaneous drug eruptions, Idiopathic facial dermatitis, Intertrigo, Periocular leukotrichia, Preauricular alopecia, Urticaria pigmentosa, Apocrine nevus, Follicular mucinosis, Lentigo simplex, Lymphocytic mural folliculitis, Acquired pinnal folding, Junctional epidermolysis bullosa, Metastatic calcinosis, Feline auricular chondritis, Erythema multiforme, foreign body reactions, vasculitis, idiopathic nasal scaling in bengal cats
