Why does my dog lick his paws constantly?

Occasional paw licking after a walk is completely normal — dogs groom themselves. But constant, obsessive paw licking that causes red-brown staining of the fur, hair loss, or skin thickening is a symptom that needs investigation.

The most common cause: allergies

Chronic paw licking is the hallmark sign of allergic skin disease in dogs. The paws are particularly affected because they are in constant contact with environmental allergens (grass, pollen, mould, dust mites). The licking causes the characteristic "Fritos" or corn chip smell — actually caused by bacteria and yeast on the moist skin between the toes.

There are three allergy types to consider:
- Environmental allergies (atopy): often seasonal; improves in winter; may accompany ear infections and facial rubbing
- Food allergies: non-seasonal; year-round; often diagnosed by an 8–12 week elimination diet trial
- Flea allergy dermatitis: one flea bite triggers intense itching; preventable with year-round flea control

Other causes to rule out

- Interdigital cyst or furuncle — a painful swelling between the toes, often caused by a foreign body (grass seed), secondary infection, or allergy. Requires veterinary treatment.
- Contact dermatitis — reaction to a specific surface: lawn chemicals, de-icing salt, cleaning products. The licking starts immediately after exposure to a particular environment.
- Yeast infection (Malassezia) — thrives in warm, moist areas. The skin between the toes becomes red, inflamed, and smells musty. Responds well to antifungal treatment.
- Bacterial infection (pododermatitis) — often secondary to another underlying cause. Requires antibiotics.
- Pain — a dog that licks only one paw, especially after exercise, may have a thorn, grass seed, splinter, cracked pad, or injured nail. Examine the paw carefully.
- Obsessive-compulsive disorder (OCD) — in some dogs, paw licking becomes a self-soothing compulsion triggered by anxiety. This is usually a diagnosis of exclusion after physical causes are ruled out.

What your vet will do

Skin scraping, cytology (to identify bacteria or yeast), and allergy testing if indicated. Treatment depends on the cause: antifungals, antibiotics, allergy medication, foreign body removal, or referral to a veterinary dermatologist for complex allergy cases.