Dog Allergies in the San Gabriel Valley: Symptoms, Causes, and When to See a Vet

If you live in the San Gabriel Valley and your dog won't stop scratching, licking their paws, or shaking their head, you're not imagining things — and you're not alone. The SGV's climate is hard on dogs with sensitive immune systems. Year-round warmth, dry Santa Ana winds, urban dust, and a long grass-pollen season create near-constant allergen exposure. Plenty of dogs manage fine, but for those that don't, allergies become a recurring, frustrating problem that doesn't go away on its own.

Here's what's actually driving it, how to recognize it, and what treatment actually looks like — from a practice that sees this every week at our clinic on Main Street, a few minutes from San Gabriel.

Why SGV dogs deal with allergies more than dogs in other regions

Allergies in dogs work the same way as in people: the immune system misidentifies a harmless substance (pollen, dust mite proteins, certain food ingredients) as a threat and mounts an inflammatory response. The difference is that dogs show most of that inflammation in their skin and ears rather than their nose and eyes.

Southern California's climate creates a few specific problems. Bermuda grass and other warm-season grasses release pollen almost continuously from spring through fall, and in mild winters they barely stop. Dust mites thrive in warm, dry indoor environments — exactly what most SGV homes provide. Mold spores spike after any rain, which in our region tends to be infrequent but intense. And food allergies — most often triggered by proteins like chicken, beef, or dairy — layer on top of environmental sensitivities in many dogs, making it hard to tell what's causing what.

The result is a dog that seems chronically itchy without a clear seasonal pattern, because the triggers are present most of the year.

What dog allergies actually look like

The classic picture is a dog who licks and chews their paws, rubs their face on the carpet, scratches at their ears, or has recurring red, irritated skin. The areas most commonly affected are:

• Paws — reddish-brown staining between the toes from chronic licking; raw or inflamed skin
• Ears — recurrent ear infections (yeast or bacterial), head shaking, odor, discharge
• Groin and armpits — areas where allergens contact thin, sensitive skin during walks
• Face — rubbing on furniture, watery discharge around the eyes, redness around the muzzle
• Belly — redness, pimples, or darkened skin over time from repeated inflammation

Secondary infections are common. When dogs break the skin barrier through scratching and licking, bacteria and yeast move in. A dog with allergies often ends up being treated repeatedly for skin infections and ear infections without anyone addressing the underlying allergy — and the infections keep returning because the root cause is still there.

Environmental vs. food allergies — they're different problems

Environmental (atopic) allergies

These are triggered by inhaled or contacted allergens: grass pollen, tree pollen, dust mites, mold, cockroach proteins, and more. In the SGV, these are the most common type. Dogs with atopic dermatitis typically start showing symptoms between one and three years of age. The itching is often seasonal at first, then becomes year-round as the immune system becomes sensitized to more triggers over time.

Food allergies

True food allergies (as opposed to food intolerances, which cause GI symptoms) cause skin and ear symptoms that look identical to environmental allergies — which is why they're easy to miss. The most common culprits in dogs are chicken, beef, dairy, wheat, and eggs. Food allergies don't follow any seasonal pattern and don't improve with antihistamines. The only reliable way to diagnose a food allergy is a strict elimination diet trial — 8 to 12 weeks on a novel or hydrolyzed protein diet with nothing else — followed by a food challenge. At-home allergy tests are not a reliable substitute.

How allergies are diagnosed and treated

The first step is always ruling out other causes of itching — mange, fleas, ringworm, and bacterial skin infections can all cause similar symptoms. Once those are excluded, allergy testing becomes appropriate.

For environmental allergies, a blood test (serology) or intradermal skin test can identify which specific allergens trigger your dog's immune response. This information feeds into allergen-specific immunotherapy — a treatment program using allergy shots or sublingual drops customized to your dog's specific sensitivities. Immunotherapy is the closest thing to a long-term solution: it trains the immune system to be less reactive over months to years.

For faster symptom relief while longer-term management is established, medications like Apoquel (oclacitinib) and Cytopoint (lokivetmab) are highly effective at reducing itch in most dogs. These work differently from traditional antihistamines, which tend to have limited effectiveness in dogs. Medicated shampoos, topical sprays, and ear cleaners manage secondary infections and reduce surface allergens.

If a food allergy is suspected, a proper elimination diet trial is the next step — ideally with a prescription hydrolyzed protein or novel protein diet rather than a store-bought "limited ingredient" food, which often contains cross-contaminants.

When to come in

If your dog has been itchy for more than two weeks, has had more than one ear infection this year, or has visible skin changes (redness, thickening, hair loss, or darkening), a proper evaluation is worth doing. Allergy management works best when started before secondary infections become chronic and before the skin undergoes long-term changes from repeated inflammation.

We see a lot of dogs from San Gabriel, Alhambra, and the surrounding SGV for exactly this. Our San Gabriel area page has directions and hours. You can also book an appointment or call (626) 441-1314 to talk through what your dog is experiencing before coming in.

Questions we hear often