Double-Coated Dog Skin Problems: Undercoat Issues, Hot Spots, and Proper Grooming

Based on peer reviewed veterinary research · For educational purposes only · Updated October 2026 · 8 min read

What Is a Double Coat and Why Does It Matter for Skin?

A double coat is a two-layer hair coat made of a soft, dense undercoat and a longer, coarser outer layer of guard hairs, found in breeds such as Huskies, Golden Retrievers, German Shepherds, Samoyeds, Pomeranians, and Corgis. The undercoat insulates the dog against cold and heat, while the guard hairs repel water and dirt.

This design works well when the coat is clean and well aired. The problem is that the undercoat sits right against the skin. Loose undercoat hair that is not brushed out can felt together, hold moisture after swimming or bathing, and limit airflow to the skin surface.

From a dermatology standpoint, the coat and skin work as one system. When the undercoat is neglected, the skin beneath can become warm, damp, and irritated, which favors Staphylococcus pseudintermedius (the main cause of canine skin infection) and Malassezia pachydermatis (skin yeast).

What Causes Undercoat Problems and Hot Spots?

Undercoat problems usually come from trapped hair, trapped moisture, or both. During seasonal shedding, often called blowing coat, large amounts of undercoat release at once. If it is not removed, it forms dense clumps close to the skin, especially behind the ears, on the neck ruff, over the hindquarters, and around the tail base.

Hot spots, known medically as acute moist dermatitis or pyotraumatic dermatitis, develop when a dog licks, chews, or scratches a spot until the skin becomes red, wet, and painful. In a prospective study of 44 dogs with pyotraumatic dermatitis, the condition was frequently linked to an underlying trigger such as parasites, allergy, or ear disease, which is why the cause matters as much as the lesion (Holm et al., 2004).

Dense coats make hot spots worse because they hide the lesion, hold moisture against it, and slow healing. Our June Dog Skin Care guide covers summer heat and hot spot prevention in more detail.

How Do Veterinarians Diagnose Double-Coat Skin Problems?

Veterinarians diagnose these problems by examining the skin beneath the coat, which often requires parting or clipping the hair over the affected area. Skin cytology (examining cells from a tape or swab sample under a microscope) quickly shows whether bacteria or yeast are involved.

Additional steps may include flea and parasite checks, skin scrapings for mites, culture for stubborn infections, and a review of allergy history. Because hot spots are usually a secondary problem, your veterinarian will also look for the trigger, such as flea allergy, atopic dermatitis, or ear infection, so the lesion does not return.

Describing when the problem began, whether it appeared after swimming, grooming, or a change in weather, and how quickly it grew will help. The Dog Skin Condition Checker can help you organize what you are seeing before an appointment.

Signs and Symptoms to Watch For

Look for changes during brushing, when you can part the coat and see the skin. The table below compares common problems in double-coated dogs.

Treatment and Grooming Options for Double-Coated Dogs

Proper grooming is the first line of care. Use an undercoat rake or slicker brush and brush all the way to the skin, working in sections, at least weekly and daily during shedding season. Bathe, rinse thoroughly, and dry the undercoat completely, since a damp undercoat holds moisture against the skin for hours.

Resist the urge to shave. Clipping a double coat removes the layer that shields the skin from sun and heat, and in some dogs the coat regrows slowly or unevenly (Miller et al., 2013). Ask your groomer for thinning and de-shedding rather than a full shave unless a veterinarian advises it.

When localized bacterial or yeast overgrowth is present, a topical antiseptic can support the skin once the hair is parted. Chlorhexidine Spray contains chlorhexidine gluconateand ketoconazole. Chlorhexidine disrupts bacterial cell membranes, while ketoconazole blocks ergosterol synthesis in yeast. It is an FDA-registered over-the-counter veterinary drug and should be used as directed. Do not apply it to deep, open, or severely painful lesions without veterinary advice. For breed-specific grooming context, see Wire-Haired Dog Skin Care and our hot spots in dogs page.

Prevention and Long-Term Management

Prevention depends on keeping the undercoat clean, loose, and dry. Brush on a schedule, increase frequency during spring and fall shedding, and make post-swim drying part of every outing. Keep dogs on year-round flea control, because fleas are a leading trigger for hot spots.

Check the skin weekly while you brush. Early redness is far easier to manage than an established hot spot. Keep a short record of any patches and whether they return in the same place, since repeated lesions point to an underlying cause. Our Excessive Shedding in Large Breed Dogs guide explains when heavy shedding is normal and when it needs attention.

Frequently Asked Questions

Should I shave my double-coated dog in summer?

Generally no. The coat insulates against heat as well as cold, and shaving can cause uneven regrowth in some dogs. Ask your veterinarian or groomer about thinning instead.

Why does my husky get hot spots?

Dense undercoat traps moisture and heat against the skin. Triggers include fleas, allergies, ear disease, and swimming without thorough drying.

How often should I brush a double-coated dog?

At least weekly, and daily during seasonal shedding, brushing all the way to the skin to remove loose undercoat.

Is shedding in double-coated dogs normal?

Yes, most shed heavily once or twice a year. Patchy bald areas, scaling, or itching are not normal and should be checked.

Sources

1. Holm BR, Rest JR, Seewald W. A prospective study of the clinical findings, treatments and histopathology of 44 cases of pyotraumatic dermatitis. Veterinary Dermatology. 2004;15(6):369-376.
2. Miller WH, Griffin CE, Campbell KL. Muller and Kirk's Small Animal Dermatology. 7th ed. Elsevier; 2013.
3. Hnilica KA, Patterson AP. Small Animal Dermatology: A Color Atlas and Therapeutic Guide. 4th ed. Elsevier; 2017.
4. Hillier A, Griffin CE. The ACVD task force on canine atopic dermatitis (I): incidence and prevalence. Veterinary Immunology and Immunopathology. 2001;81(3-4):147-151.

Related Reading

• June Dog Skin Care: Summer Heat, Swimming Prep, and Hot Spot Prevention
• Wire-Haired Dog Skin Care: Stripping, Grooming, and Unique Dermatology Needs
• Excessive Shedding in Large Breed Dogs: Causes and What Helps

E. Maddens

Founder of Vetified. Develops topical antifungal and antimicrobial formulations for companion animals. Vetified products are listed on DailyMed and manufactured through FDA-registered facilities in the United States.

Research basis: All Vetified content references peer reviewed research published in journals including Veterinary Dermatology, JAVMA, and Journal of Small Animal Practice.