Cyclic follicular dysplasia - This type of follicular dysplasia is thought to be caused by the amount of daylight exposure to the dog due to the onset in late fall or early spring with recovery generally 6 months from onset. Unlike other forms of dysplasia the onset is rapid and the pet is likely to recover, in some cases melatonin treatment may provide faster recovery.
Color dilution dysplasia - This type of follicular dysplasia is very poorly understood however, appears to be caused by macromelanosomes of the hair shaft, leading to brittleness and fracture. This condition has a gradual onset from the ages of 1-3 years old and often leads to complete hair loss in all dilute-colored areas of the coat, but mainly affects the trunk.
Complications that may arise from this form of follicular dysplasia are papules and pustules in the affected areas of the coat and in some cases pyoderma and pruritus. Breeds that may be predisposed to this condition are mainly those that have a blue or fawn coat and include Doberman Pinschers, Yorkshire Terriers, Chihuahuas, Italian Greyhounds, Newfoundlands, Salukis, and Miniature Pinschers
Black Hair Follicular dysplasia – This condition is thought to be caused by a genetic defect affecting the formation of the hair shaft and transfer of melanin. This condition has an earlier onset, with puppies usually becoming affecting by 1 month of age. This condition causes hair loss specific to black hairs and in affected dogs, complete black hair alopecia occurs by 8-9 months of age. Breeds that may be predisposed to this condition are those with bi or tri-coloured coats.
Follicular lipidosis of Rottweilers - This is a rare, breed specific condition that affects the tan areas of the animal’s face and legs causing localized alopecia. This condition causes clinical signs to develop and progress early in life and over the first 9 months of age.