Alopecia X is the name many veterinary dermatologists have given to the hair cycle abnormality that affects primarily Nordic breeds and Toy or Miniature Poodles. Other names for this condition in the veterinary literature have included Adult Onset Growth Hormone Deficiency, Growth Hormone-Responsive Alopecia, Castration-Responsive Alopecia, and, more recently, Adrenal Hyperplasia-Like Syndrome. You may be more familiar with the breeders’ terminology of Coat Funk of Malamutes or Black Skin Disease of Pomeranians. The term I prefer is Hair Cycle Arrest.
Alopecia X affects dogs of both sexes regardless of neuter status. The hair loss can first occur as early as 1 year of age or as late as 10 years of age. The primary clinical presentation is the symmetrical gradual loss of hair over the trunk and caudal thighs, sparing the head and front limbs. Sometimes the guard hairs are lost first leaving a soft "puppy" coat. The skin may become intensely hyperpigmented. There are no systemic signs associated with this condition. If your dog is not eating or drinking or eating and drinking excessively, is depressed, or has elevated liver or kidney values, then it is important to look for another cause of the hair loss.
The cause of the hair cycle arrest is unknown at this time. It is our hope through research and clinical trials that we will gain a better understanding of the cause of the hair loss and perhaps develop a truly effective treatment.