Figure 6: Diagnosing Allergic Skin Disease in the Feline Patient
Figure 6 shows an algorithm for diagnosing allergic skin diseases in cats, which consists of the following steps:
- Clinical History and Dermatologic Physical Examination
A detailed history, including a review of previous medical records, should be obtained. Information regarding seasonality, pruritus level, ectoparasite prevention, and response to previous therapies are all paramount in the workup of the pruritic cat. A complete physical examination, including flea combing and otoscopic examination, should be performed. Remember to assess the oral cavity for granulomas and indolent ulcers.
- Minimum Dermatologic Database
A minimum dermatologic database should be collected based on reaction patterns, to include skin cytology, skin scrapings, ear cytology (if ear disease is present), and DTM (Dermatophyte Test Medium) culture if indicated.
- Treat Pruritus
This is a key aspect of managing both the patient’s and pet caregiver’s quality of life and should be treated during the diagnostic period.
- Treat Secondary Infections and Ectoparasites
Secondary bacterial and yeast infections and otitis externa must be treated concurrently with controlling pruritus and diagnosing the underlying allergic disease. It is essential to rule out external parasites (i.e., fleas and mites) in all cases of feline pruritus. Prescribe a flea preventive and discuss compliance with the client.
- Recheck, Verify Medication, and Assess Response to Treatment
Flea preventives should be continued year-round in flea-endemic areas. A skin biopsy is recommended in cases with atypical lesions to rule out other pruritic dermatoses.
- Diet Trial
Diet trials should be conducted for 4-12 weeks and a food challenge performed to confirm the diagnosis if there is a positive response.