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Dog Losing Hair Near Mouth (Here’s Why)

By Patricia Williams
Last updated: November 1, 2025

When you notice your dog losing hair near the mouth, it can be worrying — especially if the skin looks irritated, red, or moist.

We outline the common causes of hair loss near a dog’s mouth, what you can do at home, and when to seek veterinary help.

Table of Contents

Dog Losing Hair Near Mouth — Why It Happens

Dogs lose hair near their mouth when the skin becomes irritated by allergies, saliva, infections, parasites, or repetitive rubbing or licking. Moisture and friction weaken the hair follicles, causing the hair to fall out in patches. Allergies, yeast infections, and bacterial infections commonly affect the muzzle because the skin stays damp after drinking, grooming, or chewing.

Some dogs also develop hair loss from rubbing their face on carpets, grass, or furniture. Without prompt treatment, the irritation can progress to redness, swelling, odor, and more widespread hair loss.

Dog Losing Hair Near Mouth: Common Causes

Saliva Staining and Moisture Dermatitis

Constant moisture around the mouth is one of the biggest contributors to hair loss in this area. Saliva from licking, drooling, or grooming can irritate the skin and break down the hair shafts.

When the skin stays wet for long periods, it becomes a perfect environment for bacteria and yeast to grow, leading to redness, itching, and eventual hair loss.

Dogs with long facial hair or heavy jowls (like Bulldogs, St. Bernards, or Pugs) are especially prone to moisture-related hair loss. You may notice a brownish stain around the mouth, a sour smell, or the dog rubbing the area with its paws.

Food Allergies

Food allergies can cause inflammation and itchiness around the muzzle because the skin comes in direct contact with food allergens during eating.

If a dog is allergic to ingredients like chicken, beef, dairy, wheat, eggs, or soy, the immune system overreacts, creating itchy, irritated patches around the lips and chin.

Hair loss, redness, small bumps, and constant face-rubbing are classic signs. Many owners notice their dog scratching the area after meals or licking excessively.

Because food allergies often cause chronic facial irritation, the hair around the mouth can become thin, patchy, or completely bald if untreated.

Contact Dermatitis

Anything that touches the skin around the mouth can trigger contact dermatitis. Plastic food bowls are a major culprit — some dogs react to chemicals in low-quality plastic or to bacteria trapped in scratches on the bowl’s surface.

Other triggers include:

• household cleaners
• pollen or grass
• grooming sprays
• scented wipes

When the skin reacts, it becomes itchy and inflamed, leading the dog to rub or scratch the area.

Over time, hair falls out from mechanical damage and irritation. Dogs with sensitive skin or allergies are more prone to this condition.

Yeast (Malassezia) Infections

Yeast infections are extremely common around the mouth because the area remains warm and moist. Malassezia yeast feeds on oils in the skin and thrives when moisture becomes trapped under fur.

Signs of yeast around the mouth include:

• greasy or waxy skin
• a musty or “sweet” smell
• redness or dark discoloration
• constant licking or pawing at the face

Yeast overgrowth irritates the skin, breaks down hair follicles, and causes hair loss, especially under the lips and along the jawline.

Bacterial Dermatitis (Lip Fold Pyoderma)

Bacteria multiply rapidly in the folds and creases around the mouth, especially in breeds with loose facial skin. This can cause lip fold dermatitis, a painful condition where the skin becomes red, moist, irritated, and infected.

Hair loss near the mouth appears as:

• bald patches under the lip folds
• scabs or crusts
• foul odor
• moist, sticky skin

Because dogs scratch or rub the area to relieve discomfort, the hair continues to fall out until the infection is treated.

Parasites

Demodex mites often target the face, making them a leading cause of hair loss near the mouth. Puppies and dogs with weakened immune systems are especially vulnerable.

Signs include:

• smooth circular bald patches
• mild redness or scaling
• increased licking or rubbing of the muzzle

Sarcoptic mange (scabies) can also cause intense itching on the face, leading to fast hair loss. Even fleas can cause irritation around the mouth if the dog scratches the area repeatedly with its paws.

Face Rubbing and Behavioral Irritation

Some dogs develop hair loss simply from rubbing their face against carpets, furniture, or rough surfaces. This often happens due to minor irritation, boredom, or anxiety — but the friction alone can break down hair fibers.

You may notice:

• thinning hair around the mouth
• red or scuffed skin
• the dog dragging its face along surfaces

If rubbing becomes frequent, the hair in the area can fall out in patches.

What to Do If Your Dog Is Losing Hair Near the Mouth

Start by gently checking the area for redness, moisture, odor, or bumps. Keep the area clean and dry — wiping the mouth after meals or drinks can help reduce irritation. If you suspect plastic bowl irritation, switch to stainless steel or ceramic.

If food allergies may be involved, avoid new treats or ingredients and consider a simple-ingredient diet while monitoring changes.

For dogs with excessive licking or moisture, daily cleaning of the muzzle and jawline using a mild, pet-safe antiseptic wipe can help prevent infections.

Try to limit scratching or face rubbing, as this prolongs hair loss. If your dog seems uncomfortable, itchy, or painful, professional treatment will be necessary to stop the cycle of inflammation and irritation.

When to Call or Visit Your Vet

You should contact your vet if:

• the hair loss is spreading
• the skin looks raw, red, swollen, or moist
• there is a foul odor
• your dog is constantly licking or rubbing the area
• bumps, crusts, or scabs develop
• the dog shows signs of pain when the area is touched

Because face infections and allergies worsen quickly when untreated, early treatment prevents chronic irritation and helps hair regrow normally.

Key Takeaway

Hair loss near a dog’s mouth is usually linked to moisture, allergies, infections, parasites, or irritation from rubbing or contact with certain materials.

Because the muzzle stays warm and damp, even minor irritation can lead to rapid hair loss. Keeping the area clean, addressing allergies or infections early, and reducing licking or rubbing will help the skin heal and allow the hair to grow back sooner. With the right care, most dogs recover fully and comfortably.