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44 Alopecia X

Client Education SUGGESTED READING AUTHOR: Brandy R. Sobczak, DVM
• If pets are symptomatic, have them seen by Mensching D, et al: Breathe with ease when managing EDITOR: Tina Wismer, DVM, MS, DABVT, DABT
VetBooks.ir • Teach proper dosing if owners are administer- June:369-373, 2007.
a veterinary staff immediately.
beta-2 agonist inhaler toxicoses in dogs. Vet Med
ing albuterol to patients at home to avoid
overdosing.

Alopecia X Bonus Material
Online

BASIC INFORMATION
PHYSICAL EXAM FINDINGS Initial Database
Definition • Often starts with gradual loss of primary • History and physical examination findings
Acquired, progressive, noninflammatory alo- hairs progressing to complete alopecia of the • Ruling out other differentials (may require
pecia of unknown cause seen typically in neck, tail, perineum, and caudal thighs. CBC, serum chemistry panel, urinalysis,
double-coat and dense-undercoat dogs and • Partial to complete alopecia of the entire thyroid and adrenal function evaluation)
miniature poodles. Myriad names, etiopatho- trunk and tail, sparing the head and fore-
geneses, diagnostic procedures, and therapeutic limbs, eventually develops. Advanced or Confirmatory Testing
modalities have been proposed, with varied • Hyperpigmentation is common. • Skin biopsies are generally recommended to
validity and outcomes. • Scaling and superficial pyoderma are occa- seek characteristic changes and rule out
sionally noted. common differential diagnoses, notably
Synonyms • No systemic signs of illness sebaceous adenitis.
Hair cycle arrest, congenital adrenal hyper- ○ Histopathologic analysis typically reveals
plasia, growth hormone–responsive alopecia, Etiology and Pathophysiology nonspecific changes of endocrinopathy.
hyposomatotropism of the adult dog, pseudo- • Etiopathogenesis of this condition is Excessive trichilemmal keratinization
Cushing’s, follicular dysplasia of Nordic breeds, unknown. (flame follicles) seen in many cases of
follicular growth dysfunction of plush-coated • Previous hypotheses such as growth hormone alopecia X is suggestive but not pathog-
breeds, black skin disease of Pomeranians, deficiency or hydroxylase-21 abnormality nomonic of this disorder.
castration-responsive alopecia, coat funk in have been abandoned. • Sex hormone panels (baseline and post
Alaskan malamutes • Current popular hypotheses include a genetic adrenocorticotropic hormone stimulation)
predisposition to local follicular receptor have been recommended in the past, but
Epidemiology dysregulation. usefulness has recently been questioned.
SPECIES, AGE, SEX
• Dogs, both sexes, intact or neutered DIAGNOSIS TREATMENT
• Onset at 1-10 years of age
• Breeds at greater risk include Pomeranian, Diagnostic Overview Treatment Overview
chow chow, keeshond, Samoyed, Alaskan The diagnosis of alopecia X is by exclusion of The therapeutic approach is highly empirical.
malamute, Siberian husky, and miniature other alopecic disorders. Numerous treatment modalities have been
and toy poodles. proposed; none is always effective.
Differential Diagnosis
Clinical Presentation • Endocrinopathies (hypothyroidism, hyper- Acute General Treatment
HISTORY, CHIEF COMPLAINT adrenocorticism, hyperestrogenism) • Neutering of intact dogs may induce per-
Patients are generally presented because of • Sebaceous adenitis manent or temporary hair regrowth in
owner-observed hair loss. • Other follicular dysplasias ≈50%-75% of cases.

A B C
ALOPECIA X Alopecia X in 4-year-old, castrated male Pomeranian. Note alopecia affecting the neck (A), abdomen
(B), and caudal thighs (C). (Copyright Dr. Manon Paradis.)

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