Photo 5: Follicular dysplasia can be seasonal or cyclical int he Boxer and English Bulldog breeds. Alopecia can be seen symmetrically
on the trunk, ventral neck or caudal thighs.
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Follicular dysplasia This is a quite common hair follicle disorder that definitely has a genetic basis, as seen by the marked breed predilection.
Dobermans (blue and fawn colored), Rottweilers, Siberian Huskies, Malamutes, Chesapeake Bay Retrievers, Labradors, Portugese
Water Dogs and others are predisposed.
It can be seasonal or cyclical in the Boxer and English Bulldog breeds. The condition starts farily early on in age, around 1 or 2 and is slowly progressive. Alopecia can be seen in various locations
but mostly symmetrically on the trunk (lateral trunk and flank area), ventral neck or caudal thighs (Photo 5). Hyperpigmentation
is uncommon and can be more readily seen in the flank areas in the Bulldog breed. Color dilution alopecia is a form of dysplasia
seen in the Doberman breed, Yorkshire Terrier, Chihuahua, Saluki, Irish Setter and Chow Chow that has accompanying abnormal
pigmentation with odd coat color. In the areas of alopecia, crusts, papules and pustules from pyoderma can complicate the
condition. Diagnosis is made on clinical examination, trichograms (examination of hairshafts under light microsopy) and skin
biopsy. Treament is not recommended except for concurrent pyoderma. 
Photo 6: Alopecia X is not only frustrating, it is poorly understood. The alopecia can start at an early age and remain progressive.
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Alopecia X Alopecia X (growth-hormone/castration responsive dermatosis, adrenal sex hormone alopecia, pseudo-Cushing's) has to be the
most frustrating area to discuss, as this condition is poorly understood and has many names! Classically, this was first described
in the early 1980s at the University of Tennessee in the Pomeranian breed. The affected dogs were young adults and had striking
alopecia on the trunk, ventral neck, caudal thighs, and lateral trunk. In the original studies in the affected Pomeranians,
abnormal sex hormone results were seen with ACTH stimulation. The affected dogs had exaggerated and elevated levels of progesterone
and certain androgens.
Research in humans with a similar condition suggests a deficiency or partial deficiency in adrenal enzymes. Thus, at one point
it was speculated in the dog a deficiency of 21- dehydroxylase was present resulting in abnormalities in steroidogenesis and
ultimately abnormally high levels of certain adrenal gland sex hormones. Therefore, the term adrenal gland hyperplasia-like
syndrome was also coined recently! Unfortunately, some normal appearing Pomeranians also had some of these abnormal hormonal
levels and recent evidence suggests the condition may not be related to just elevated progesterones and androgens. Moreover,
treatment response based upon sex hormone levels often fail. As a result, and in conjunction with insufficient data since
this original study, there is a fair amount of confusion and controversy. The alopecia can start at an early age and be progressive. Initially, alopecia may involve only the primary or guard hairs
giving the dog a "puppy coat" appearance Photos 6 and 7, p. 16S). Affected areas can be very scaly and pustules and papules
can also be seen. Diagnosis is made generally with skin histopathology but ruling out other conditions may be needed as well.
These can include hypothyroidism, Cushing's disease and follicular dysplasia. Treatments can include neutering, melatonin,
oral methyltestosterone and even Lysodren. All have ocassionally resulted in partial or complete regrowth of hair but alopecia
may redevelop while on therapy. 
Photo 7: Virtual complete lack of guard or primary hairs is evident on the lateral trunk of this adult Chow Chow.
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Post-clipping alopecia This condition is relatively straightforward and occurs after areas on the dog are clipped or shaved. It is most commonly
seen on the trunk or limbs (in areas that are mostly commonly clipped). Specific breeds are affected and include the Nordic
breeds that are plush coated. These breeds include Siberian Husky, Samoyed, Malamute, Keeshond and also the Chow Chow, Labrador,
and German Shepherd. Areas of alopecia are noted several months later after clipping was performed along with variable degree
of hyperpigmentation.
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