Skin and allergies
Itchy Skin and Allergies in Dogs and Cats
Why itching is a symptom rather than a diagnosis, and how vets work through the common causes.
General information
Itching has several common causes: parasites, bacterial or yeast infection, food allergy and environmental allergy (atopic dermatitis). More than one is often present at the same time, which is why a single treatment frequently disappoints.
Symptoms
Beyond obvious scratching, look for:
- Licking or chewing paws, often staining the fur reddish-brown
- Recurrent ear infections — in dogs these are very often allergy-driven
- Rubbing the face on furniture or carpet
- Hair loss, scabs or thickened, darkened skin
- In cats, over-grooming that leaves symmetrical bald patches
Diagnosis
Vets usually start by eliminating parasites and infection, then run a strict elimination diet trial for eight to twelve weeks using a novel or hydrolysed protein, with absolutely no other foods or flavoured treats. Skipping steps makes the result uninterpretable.
Allergy blood and intradermal tests identify targets for immunotherapy in already-diagnosed atopic animals; they are not screening tests for diagnosing allergy.
Treatment and expectations
Atopic dermatitis is managed rather than cured. Modern options include targeted medications, immunotherapy, medicated shampoos and essential fatty acid supplementation. The realistic goal is comfortable skin with occasional flare-ups.