Itching is a very common response to skin inflammation. There are a few broad categories of skin diseases that can cause this inflammation, including parasite infection (fleas, mites, ticks), bacterial infection, yeast infection, and allergies. Frequently, several of these processes may be present at the same time. Common signs include licking the feet, head shaking, scratching, the presence of a rash on the belly, and recurrent ear infections.
Under normal circumstances, a population of bacteria and yeast lives on the skin and the numbers are kept in balance by the body’s defenses. Once the skin becomes inflamed, regardless of the underlying reason, these bacteria and yeast tend to overgrow which exacerbates the itching. Your pet’s response to itching is to scratch, which worsens inflammation and makes the area itchier…thus the cycle starts and the itching gets worse very rapidly. Incidentally, the external ears are part of the skin system, and the same problems that affect the skin often affect the ears.
Our main goals with itchy pets are i) to identify the underlying reason for the itching ii) to identify and control bacterial or yeast overgrowth that may exacerbate the problem.
3 non-invasive tests are usually performed to help answer these questions:
i) Skin scraping: this test collects material from the skin to examine microscopically for mites (Demodex or Sarcoptes)
ii) Skin cytology: this test collects material from the skin to examine microscopically for bacterial or yeast overgrowth
iii) Ear cytology: material collected from the external ear is examined microscopically for bacterial or yeast overgrowth
Based on these results therapy may include:
• Shampoo or other topical therapy
• Oral antibiotics or antifungals
• Oral antihistamines or steroids to help with itching
• Flea medications to rule out Flea Allergy Dermatitis as an underlying factor
If the symptoms recur, further evaluation for allergies may be advised. Allergies may be to flea bites, environmental factors (pollen, grasses, dust, etc), or even food. In people, allergies primarily cause sinus problems and itchy eyes, whereas in our pets, the skin is the primary allergy organ. This inflamed skin then provides an ideal environment for bacterial and yeast overgrowth, perpetuating the itch/scratch cycle.
Allergies are treatable. There are several strategies that include hyposensitization (allergy injections, similar to what humans receive), hypoallergenic foods, and medications to decrease the overactive immune response.
Medical progress exams are very important in the treatment of skin disease to ensure that bacterial or yeast overgrowths have been treated sufficiently and try to minimize flare-ups.