All dogs experience some degree of hair loss in the form of shedding.
“Normal dogs shed hair all year long,” says Dr. Kathryn Primm, owner and practicing veterinarian at Apple Brook Animal Hospital. “Especially indoor dogs who are less exposed to extremes of temperature and day length changes. When hairs become old or damaged, they fall out. It is a normal process.”
However, if the amount of hair on your sofa has gone from a light dusting to a full-on blizzard, it could be a result of one — or more — of these eight causes.
1. Breed-Specific Hair Loss
Some dogs lose more hair than others based on their breed. Your average short-haired Labrador or Beagle sheds much more than a Poodle or Schnauzer because these breeds have completely different hair-types.
Dogs bred to withstand harsh temperatures like Huskies and Malamutes have coats that thicken in winter, then thin out in the spring with an epic mass-shedding event known as coat blow. Some even experience a second coat blow in the fall.
There are also several breeds known to have genetic predispositions to certain types of alopecia (the fancy term for hair loss), including Doberman Pinschers, Boxers, Chihuahuas and Bulldogs.
Dogs may lose hair as a reaction to an infestation of fleas or skin mites. When fleas bite, their saliva causes an immune response within the body. Pups that are allergic to flea saliva develop a full-body reaction with intense itching and inflamed skin. They often suffer from hair loss, sores and infections as a result of licking, scratching and chewing at their skin.
Demodex mites live in the hair follicles of dogs. Young puppies and immune-compromised adults sometimes experience an overgrowth of mites and develop a condition known as Demodectic mange which causes lesions, thickening of the skin and hairloss.
Demodex cannot be transferred between dogs or to humans, but another common mite is highly contagious to other pets and family members! Infestation with Sarcoptes mites is commonly referred to as Sarcoptic mange or scabies. It is extremely itchy and causes sores, crusts and patchy hair loss.
In addition to parasites of the skin, intestinal worms may also lead to poor coat health and increased shedding by damaging the dog’s ability to process nutrients.
Dr. Primm recommends seeing your vet at the first sign of these pesky parasites:
“Any dog with skin lesions should be evaluated by a veterinarian to protect him and your human family. Early intervention is critical to minimize suffering and ensure effective treatment.”
Allergies are a common and persistent problem for many dogs. Like humans, dogs can be allergic to just about anything, from ingredients in their food to environmental factors. While there can be respiratory symptoms, dogs more commonly have skin reactions when exposed to allergens. The body reacts to offending substances by releasing histamine into the bloodstream which results in itching and excess shedding.
Cooler weather may provide some relief for dogs with seasonal allergies, but those with food sensitivities or reactions to indoor stimuli may suffer year-round.
“It is less likely to be a problem in the winter because a lot of dogs are allergic to spring through fall allergens, like molds and pollens,” says Dr. Primm. “But if your dog is allergic to something in his food or house dust (non-seasonal allergy), you might not see a difference in the winter. The excessive shedding will usually be accompanied by pruritus (itching) and possibly recurrent ear infections, itchy eyes and paw licking.”
4. Poor Nutrition
Undernourishment is rarely a problem for dogs in loving homes unless there is competition from other pets. However, some pups have stricter dietary needs than others. Growing puppies require higher calories, protein and fat to help them develop, and dogs with certain medical conditions may also need adjustments to their diets in order to maintain healthy skin and hair.
“Overall health status and diet can also play a role in the hair coat,” Dr. Primm says. “All dogs should eat a premium, high-quality or homemade diet, and the owner should understand that you ‘get what you pay for’ with economy pet food.”
Finding the perfect diet for your individual dog’s needs can be complicated. Speak to your vet for tips and recommendations.
5. Bacterial or Fungal Infections
Ringworm is not listed along with fleas and mites because it is actually a fungal infection, not a type of parasite. It causes circular patches of itchy, inflamed skin and hair loss. Although more common in puppies, ringworm can occur in any dog and is highly contagious to humans and other pets.
Skin infections caused by the Staphylococcus aurea bacteria often closely resemble ringworm lesions. Staph is present everywhere, but in order for an infection to develop, the bacteria must be introduced into the body through irritated or abraded skin – typically from the dog licking, chewing or scratching.
Should you notice round, scaly patches of hairloss and irritation on your dog’s skin, see your vet for diagnosis and treatment.
6. Hormone Fluctuations
Mama dogs often experience hair loss related to hormonal changes during pregnancy and nursing. The hair follicles go into a resting phase to reserve as much energy as possible for the puppies. This causes the coat to shed heavily, similar to the seasonal coat blow seen in many double-coated dog breeds.
There are also several imbalances related to the sex hormones of male and female dogs that may cause them to lose excessive amounts of hair. If your veterinarian suspects this to be the cause of your dog’s hair loss, he or she will start reproductive hormone therapy and likely recommend a healthy dietary protocol as well as supplementation with omega fatty acids.
7. Certain Illnesses
As much as we hate to think of our dogs suffering from a serious medical condition, there are a few diseases that cause abnormal hair loss.
“There are metabolic disorders that affect the health of the hair coat, like hypothyroidism and Cushing’s Disease,” Dr. Primm explains. “These are diseases that have other, even more serious consequences, so it is important to see your vet for wellness care and screening every year and more frequently if you notice changes in your dog’s appetite, thirst, energy level or other changes.”
Hypothyroidism is quite common in dogs and occurs when the thyroid gland fails to produce adequate amounts of hormones. Dogs with Cushing’s Disease suffer from an overproduction of corticosteroids in the adrenal glands. Pets taking long-term prescribed steroids for other health problems are at an increased risk for Cushing’s.
8. Stress-Related Hair Loss
If your dog has been thoroughly examined by a vet and the cause of his excessive hair loss is still a mystery, it could be a sign of stress. Severe anxiety from separation or changes in the home can manifest as physical symptoms including vomiting, diarrhea, and compulsive scratching or licking.
Not only will this behavior cause bald patches, dogs that obsessively lick one particular spot on the body may give themselves lesions or skin infections known as acral lick dermatitis.
Some dogs battle anxiety throughout their lives, while for others it is related to a specific trigger. Ask yourself if your schedule has recently changed or if there may be a stressor at home like a construction project, a new baby, or the loss of another pet. Your veterinarian can treat the physical symptoms and recommend medications, natural supplements, or a consultation with a professional behaviorist.