Treating canine hair loss begins by determining the cause, which could be flea allergic dermatitis, poor nutrition or a metabolic disease.
Canine hair loss after demodex infection. I have a 5 month old pug which has been diagnosed and treated successfully for demodex.Is canine hairloss common in Bullmastiff Dogs? I have a female bullmastiff and she is losing patches of hair.

Canine hair loss causes.A Lab losing hair may be diagnosed with alopecia, and the causes of this condition can be varied in canines. In some cases, parasites like mites, fleas, or ticks could be embedded in your dog's fur, which can lead to itching and scratching and Labrador hair fall.

Two causes of hair loss that can be treated with melatonin. In dogs, melatonin may help manage two conditions that cause hair lossseasonal flank alopecia and alopecia X. In both cases, the condition is considered cosmetic.

The first step in addressing canine hair loss is seeking professional guidance. A veterinarian can conduct a thorough examination, including skin tests and blood work, to identify the root cause of the issue. Nutritional Evaluation
Harrison S., Bergfeld W. Diffuse hair loss: Its triggers and management // Cleveland Clinic Journal of Medicine.Pattern Hair Loss in Men // Dermatologic Clinics.