You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

The type and distribution of skin lesions in cats with pruritus can be helpful in suggesting the likely cause.   

In dogs pruritus is usually manifest by scratching, biting and rubbing. In cats pruritus is often manifest as increased or altered grooming behaviour, and sometimes with scratching. Excess grooming leads to :

• Hairball formation
• Alopecia
• Coat colour changes 
• Miliary dermatitis
• Eosinophilic plaques
• Excoriations

The type and distribution of pruritic lesions often helps to indicate the likely causes of the pruritus :

 

Lesion Type	Distribution	Causes
Alopecia	Bilaterally symmetrical	Systemic disease - allergies, demodex, ectoparasites, fungal infections (eg ringworm), malassezia.
Eosinophilic dermatitis - may not be pruritic	Face, ears, feet  Localised indolent ulcers	Mosquito bite hypersensitivity Idiopathic, ? allergy
Hypereosinophilic syndrome - rare	Excoriations, erythema and plaques	Unknown - Signs include systemic eosinophilia, anorexia, vomiting, diarrhoea, weight loss
Erosions, ulcers due to self trauma	Head and neck	Atopy, drug hypersensitivity, food allergy, otitis externa/media, parasites (chyletiella, demodex, flea allergy, notoedres), ringworm, tumours (mast cell tumours, T-cell lymphoma)
Miliary Dermatitis - the most common lesion associated with pruritus in cats	Neck, along dorsum of back, tailbase, generalised	Allergies - atopy, food allergy, contact dermatitis, drug reaction,  Infections - folliculitis, fungal infections (ringworm) Parasites - flea allergy (most common cause), chyletiella, demodex, otodectes, notoedres.
Nodules - rare	Localised	Mast cell tumours (Siamese) Rare causes - cryptococcus infection, mycetoma, collagenolytic granuloma.
Scale and crusting lesions	Localised or generalised	Chyletiella, malassezia, ringworm, immune disorders (pemphigus foliaceus, systemic lupus erythematosus (SLE)) , sebaceous adenitis, seborrhoea, T-cell lymphoma
Other occasional causes (rare)	Variable - usually localised	Cauda equina syndrome Chin acne Feline hyperaesthesia Feline ulcerative dermatitis - oftyen not pruritic Obsessive compulsive disorders Urticaria pigmentosa

Updated October 2013