Hair loss (i.e., alopecia) in your furry pal can be concerning, especially when you aren’t sure of the underlying cause. Shedding is normal for most cats and dogs, but excessive hair loss that leads to bald patches may indicate an underlying health problem. Our Stanton Pet Hospital team shares possible causes, diagnostic tests, and treatment options for pets’ hair loss.

What causes hair loss in pets?

Pets’ fur grows in cycles, including active growth, dormant phase, and shedding phases. Although hair growth and shedding may increase or decrease seasonally, hairs exist in a mix of phases so that new ones grow in when old hairs fall out. Hair loss occurs when those phases are thrown out of balance or when disease or inflammation damages the hair follicles. Pets’ common hair loss causes include:

  • Parasites — Fleas, ticks, and mites cause itching in pets, leading them to chew, lick, scratch, and pull at their fur. 
  • Allergies — Environmental, food, or flea allergies lead to widespread and chronic skin inflammation. Over time, skin can become thickened and scarred, causing hair to fall out.
  • Infections — Bacterial, fungal, or yeast skin infections often cause crusting and scaling, sometimes resulting in dramatic or patchy hair loss. Skin infections typically occur secondary to underlying disorders, including allergies. 
  • Hormonal imbalance — Hypothyroidism, hyperthyroidism, and Cushing’s disease can disrupt hormone levels and alter the hair growth cycle, leading to thin or missing hair.
  • Nutritional deficiencies — Fatty acid, vitamin, mineral, or macronutrient imbalances can lead to coat changes. Poor diet quality and malabsorption disorders can also contribute to nutritional deficiencies.
  • Stress or anxiety — Emotional stress, anxiety, or environmental changes can trigger excessive grooming behavior in pets, leading to hair loss attributable to self-trauma.
  • Genetics — Some pets are prone to hereditary conditions that cause hair loss such as alopecia X, pattern baldness, follicular dysplasia, or flank alopecia. Genetic hair loss disorders typically don’t require treatment.

Diagnosing hair loss in pets

Hair loss diagnosis requires a history, physical exam, and diagnostic workup. Recommended testing depends on whether your pet shows other skin or hormonal disease signs, such as itching or inflammation, or if the condition appears characteristic of a harmless alopecia syndrome. Possible tests include:

  • Skin scraping to check for parasitic mites.
  • Skin cytology to check for bacterial or yeast infections.
  • Fungal culture to check for ringworm (i.e., dermatophytes).
  • Skin biopsy to learn about skin and follicle cell structure.
  • Blood work and urinalysis to assess endocrine function.
  • Allergy testing to identify environmental allergy triggers.

Pet hair loss treatment options

Whether pet hair loss responds to treatment depends on the underlying cause and severity. Hair loss with an inflammatory cause can become permanent if enough damage occurs to the follicles. Hair loss treatments may include:

  • Parasite control — Administering flea and tick preventives or mite treatments can eliminate parasites and prevent reinfestation.
  • Allergy management — Allergy treatments may include immunotherapy, antihistamines, steroids, immune modulators, dietary changes, or allergen identification and avoidance.
  • Medications — Oral antibiotics, antifungals, or topical treatments, such as shampoos, sprays, or creams, can manage skin infections and inflammatory conditions.
  • Endocrine therapies — Medications can combat altered hormone levels in conditions that cause hair loss, such as too much cortisol in Cushing’s disease or too little thyroid hormone in hypothyroidism. 
  • Nutritional supplements — Supplements, such as fatty acids, that reduce skin inflammation can complement therapy for skin disorders. Melatonin may be a useful supplement for pets with seasonal or inherited alopecia conditions.
  • Behavioral modification — Addressing underlying stress or anxiety through behavior modification techniques, environmental enrichment, or medications can reduce hair-pulling or skin-chewing behaviors.

Regular grooming, optimized nutrition, year-round parasite prevention, and routine veterinary checkups can help you maintain your pet’s skin and coat health. However, many health conditions can cause hair loss or change haircoat quality, which signals a possible underlying disorder. Contact our Stanton Pet Hospital team to schedule a visit if your pet experiences excessive hair loss, thinning hair, altered hair texture, or skin changes.