my cat has dermatitis around the ear and face

Of course. Dermatitis of the face and ears in a cat is a very common presentation, and I know how distressing it can be to see them so uncomfortable. This specific location, what we call "head and neck pruritus," is one of the classic reaction patterns in feline dermatology. While it can look dramatic, we can absolutely figure it out with a systematic approach.

My primary differential diagnoses for this pattern are:

Cutaneous Adverse Food Reaction (Food Allergy): This is very high on the list for cats with intense itching around the head and neck.

Atopic Dermatitis (Environmental Allergy): Similar to hay fever in people, but in cats, it manifests as itchy skin.

Ectoparasites: Ear mites (Otodectes cynotis) are a classic cause of ear and head itching. Flea allergy is also a major cause, even in indoor-only cats.

Dermatophytosis (Ringworm): This fungal infection can mimic many other skin diseases in cats and should always be considered.

Here is how I would approach this case:

First, we must rule out the non-allergic causes. Your primary veterinarian should perform an ear swab and cytology to check for ear mites and any secondary bacterial or yeast infections in the ear canals. They should also perform a skin cytology (an impression smear) of the affected skin to look for secondary infections that result from self-trauma. A fungal culture (DDTM) is also a crucial step to rule out ringworm.

Second, ensure your cat is on a high-quality, veterinarian-recommended flea preventive year-round. Flea control is non-negotiable in any itchy pet.

If those tests are negative and flea control is perfect, we are left with an underlying allergy. To differentiate between a food allergy and an environmental one, the next step is a strict elimination diet trial for 8-12 weeks using either a novel protein diet or a hydrolyzed protein diet. This is the only reliable way to diagnose a food allergy.

Could you provide a bit more information? Specifically, what is your cat's age, diet history (all foods and treats), and current flea prevention? Photos of the affected areas would also be incredibly helpful for me to assess the lesion type and distribution. We'll build a sustainable plan from there.