AI overview
Patchy hair loss in dogs is commonly caused by skin allergies, parasites, or underlying hormonal conditions. Frequent triggers include flea allergy dermatitis, environmental allergies, or microscopic mites causing mange. Symmetrical hair loss on both sides of the body may also indicate an endocrine issue, such as hypothyroidism or Cushing's disease.
Because these causes require very different treatments, a veterinarian should evaluate your dog's skin to reach an accurate diagnosis. Contact a vet immediately if the hair loss spreads rapidly or is accompanied by raw skin, bleeding, severe swelling, lethargy, or loss of appetite. Run a skin scan in the app to log a baseline for your vet visit.
Informational only - not a veterinary diagnosis. For urgent signs, contact a vet immediately.