Is your pet suddenly losing their hair? Don’t worry—this isn’t an infomercial—but you should pay attention. Sudden hair loss in pets can signify a number of health issues that necessitate a visit to Tidmore Veterinary Hospital.

The difference between pet shedding and hair loss

Hair loss is a natural every day occurrence for all dogs and cats—except naturally hairless breeds. So, how can you tell the difference between normal shedding and hair loss?

Hair loss that is unrelated to shedding—formally known as alopecia—is relatively easy to identify. While shedding takes place consistently over the entire body, alopecia often affects a limited area, such as the legs, feet, hind end, or flank (i.e., sides), and may be marked by skin or behavior related changes, including:

  • Itching, biting, or licking
  • Visible scabbing, flaking, hives, or redness
  • Patchy appearance
  • Abnormally greasy, dry, or dull coat
  • Thin skin
  • Discolored skin
  • Recurring ear infections
  • Other clinical signs, such as changes in appetite or weight, lethargy, vomiting, or diarrhea

The alopecia onset can also be revealing, especially if the hair loss occurs outside the pet’s normal shedding season.

Common hair loss causes in pets

Hair loss in pets can be caused by a wide range of conditions or disorders, from relatively benign to serious, with some accompanied by intense irritation and discomfort, and others pain-free. The following list, while not exhaustive, features the most common hair loss causes in pets. 

  • Parasites — Fleas and mange mites are the external parasites most often associated with alopecia, but any biting insect, including mosquitoes, lice, and ticks, can trigger localized hair loss. Fleas and mites can cause such intense discomfort that pets will scratch and pull out their hair. If your pet is not on year-round flea and tick prevention, parasites may be to blame for sudden-onset hair loss. 
  • Fleas — Flea-related hair loss often appears around the tail base, although anywhere on the trunk may be affected. Flea allergy dermatitis (FAD) is a severe allergic reaction in dogs triggered by a protein in flea saliva. Only one flea bite can cause intense itching and inflammation in flea-allergic dogs. 
  • Mites — Sarcoptic and demodectic mange are parasitic skin infections caused by microscopic mites. Mange is rarely found in healthy dogs, but can affect those who are immunocompromised. Sarcoptic mange (i.e., scabies) is highly contagious to humans. Mange-related alopecia can affect the entire body, but demodex, which commonly occurs in puppies, may first appear on the face or head.
  • Allergies — Environmental (i.e., inhalant) allergies and food allergies can cause an inflammatory reaction that drives pets to scratch, chew, and lick. Pets can be allergic to a number of unavoidable substances, including grasses, tree pollen, dust, mold, and mildew, as well as protein or carbohydrate sources in their food. Allergy-related hair loss may be localized to the feet, legs, or abdomen. Repeated irritation from licking or chewing may lead to secondary bacterial infections, inflammation, or self-inflicted wounds. 
  • Endocrine disorders — Hormonal balance changes in your pet can affect hair growth. Abnormal thyroid function, adrenal function (i.e., Cushing’s or Addison’s disease), or estrogen or testosterone fluctuations can result in non-inflammatory alopecia and skin changes such as thinning or discoloration. These conditions are often seen with other physical signs, including weight gain or loss, appetite, or energy level changes.  
  • Self-trauma — Pets may pull or pluck their own hair because of anxiety or pain. In addition to intense stress-related shedding (e.g., your pet’s heavy shedding when you visit the veterinarian), anxious pets may develop obsessive-compulsive behaviors that cause localized hair loss in easy to reach areas, such as the feet or lower legs. Although anxious pets first may behave this way only when stressed, subsequent infections and inflammation may result in more consistent behavior.

Alopecia over a specific joint can also suggest pain (e.g., arthritis), as pets lick and chew the area to find relief. 

  • Bacterial or fungal infections — Skin infections can create bald areas on your pet’s skin. Bacteria or fungal (e.g., yeast) organisms may begin on the skin’s surface, but then gradually travel to the lower dermal layers, which makes treatment more challenging. Infections may be secondary to allergies, parasites, or other irritations. 
  • Post-clipping alopecia — Grooming-related alopecia can occur when pets are clipper-shaved and their hair growth cycle is disrupted, creating a temporary or permanent alteration in hair growth (i.e., hair cycle arrest [HCA]). If the hair returns, owners may notice a change in texture or color.    

Diagnosing hair loss causes in pets

When you bring your pet with alopecia to Tidmore Veterinary Hospital, our veterinary team will ask specific questions about your pet’s clinical signs, including:

  • When did you first notice the hair loss?
  • What food and treats does your pet eat?
  • Is your pet experiencing other clinical signs?
  • Has anything changed in the home?
  • Is your pet currently on a flea and tick prevention protocol?

Our veterinarian will perform a standard exam on your pet, and also a thorough dermatological evaluation of their skin and hair, looking for visible changes, infection, or parasites. Additional testing may include blood work, skin scraping, bacterial culture, or cytology (i.e., a microscopic review of your pet’s skin cells). Based on these results, our veterinarian can formulate a targeted treatment plan to address the underlying cause for your pet’s alopecia.

Your pet’s skin is an important indicator of their overall health. Sudden changes to their skin and coat require veterinary attention to prevent worsening signs, pet discomfort, and clinical illness. If your pet’s hair is looking “barely there,” schedule an appointment at Tidmore Veterinary Hospital.