The Cat with Miliary Dermatitis

Table 2-8. Differential Diagnoses, Commonly Affected Sites, Recommended Diagnostic Tests, Treatment Options, and Prognosis in a Cat with Miliary Dermatitis

Disease

Affected Sites

Diagnostic Tests

Treatment

Prognosis

Flea-bite hypersensitivity

Dorsal lumbosacral area, caudal half of the body or generalized disease (Fig. 2-46 and Fig. 2-47)

Flea control trial

Flea control, glucocorticoids, antihistamines, essential fatty acids.

Good for well-being of the patient with continued management; guarded for cure

Atopy* (hypersensitivity to aeroallergens such as pollens, house dust mites or mold spores)

Head and neck, generalized disease.

Diagnosis based on history, physical examination and ruling out differential diagnoses. Intradermal skin test allows formulation of immunotherapy

Allergen-specific immunotherapy, antihistamines, essential fatty acids, glucocorticoids.

Good for well-being of the patient with continued management; guarded for cure

Food adverse reaction (may or may not be allergic, commonly reaction against a protein, rarely an additive, clinically indistinguishable from atopy)

Cranial half of the body or generalized disease

Elimination diet

Avoidance, antihistamines, essential fatty acids, glucocorticoids.

Excellent, if offending protein(s) is (are) identified and avoided. Only fair with continued management, if not. Guarded for cure

Mosquito-bite hypersensitivity (an allergic reaction to salivary antigens of mosquitoes)

Papules and crusts on dorsal muzzle, lateral aspects of pinnae, and foot pads (Fig. 2-48 and Fig. 2-49)

Keeping cat indoors for some days, biopsy

Indoor confinement (at least during dusk and dawn), insect repellents such as pyrethrine sprays

Good for well-being of the patient with continued management; guarded for cure

Bacterial superficial folliculitis (caused by Staphylococci and secondary to other diseases)

Head and neck or generalized

Cytology, biopsy

Antibacterial agents

Good, but relapse likely if underlying disease is not identified and treated

Otodectes cynotisinfestation (may cause more than just otitis externa)

Otitis externa, pinnae, face, neck, thighs, tail, and tailbase

Superficial skin scrapings, miticidal treatment trial

Antiparasitic agents

Excellent

Pemphigus foliaceus*

Yellowish to brownish crusts may be mistaken for the typically smaller and darker classical miliary dermatitis lesions. Head, inner pinnae, claw beds, nipples

Cytology, biopsy

Immunosuppression

Fair

Mast cell tumor*

Papular form may occasionally be mistaken for miliary dermatitis

Cytology, biopsy

Glucocorticoids, chemotherapy

Fair

Dermatophytosis (in this form typically caused by M. canis)

Focal or generalized

Cytology , Wood's lamp, fungal culture, biopsy

Antifungal agents

Guarded for cure in catteries and Persian cats, good otherwise.

Cheyletiellosis (depending on location a rare to common contagious disease caused by Cheyletiella blakei)

Typically characterized by excessive scaling particularly on the dorsum, but occasionally generalized miliary dermatitis

Superficial skin scrapings, sarcoptes treatment trial, flea combing and microscopically evaluating debris covered with mineral oil in a Petri dish

Antiparasitic agents

Excellent

Feline scabies (a highly contagious disease caused by Notoedres cati)

Pinnae, face, neck, generalized disease.

Superficial skin scrapings), sarcoptes treatment trial

Antiparasitic agents

Excellent