Interactive Case Discussion on Scaling and Crusting Dermatoses in Dogs

Crusts and scaling are caused by many different skin diseases in dogs. they can manifest as primary lesions but occur more often as secondary lesions. in order to define the list of differential diagnosis the signalment can provide useful information as in certain breeds genetically determined diseases occur such as different types of ichthyosis or dermatomyositis. Clinical symptoms of genetically determined diseases are usually already present in puppies or young dogs. the risk of neoplasia is typically larger in mid- dle-aged to old dogs. a history of skin problems in the owner or contact animals indi- cates a possible contagious disease such as dermatophytosis or ectoparasitic disease. a history of the dog being imported or spending time abroad includes leishmaniasis as a possible cause. History should also include information on earlier treatments and their effect. abnormalities found on a general examination can indicate an associated or underlying systemic disease.

diagnostic approach
A thorough dermatological examination gives information on other skin lesions and lesional distribution. asses the type of crusts present. Do they contain pus (yellow- tinged), or are they mainly dried up blood (dark red-black) or do they seem to consist of primarily keratin (grey-whitish).

• step 1: Define if the problem is associated with pruritus or not.

crusting and scaling dermatosis with pruritus

• step 2: If moderate to severe pruritus is present rule out ectoparasitic diseases first and assess presence of primary or secondary bacterial /yeast infection. indi- cated diagnostic tests are: skin scrapings, trichogramm and cytology of impression smears.
• step 3: Treat ectoparasitic infections and microbial infections if present. adequate flea control should be in place and a diagnostic therapy for ectoparasites (e.g. Sarcoptes) can be indicated. although demodicosis and dermatophytosis are usually without pruritus some dogs are pruritic.