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Recurrent Flank Alopecia, Dog 869

Recurrent Flank Alopecia, Dog
VetBooks.ir Advanced or Confirmatory Testing Diseases and Disorders

progress to an end-stage permanent flank
BASIC INFORMATION
alopecia and marked hyperpigmentation. Skin biopsies for dermatohistopathologic exam:
Definition • Occasionally, a dog may have only one • Nonspecific changes suggestive of endo-
Skin disorder of unknown origin is charac- isolated episode of alopecia during its crinopathies may be observed. Truncated,
terized by episodes of truncal hair loss with lifetime. keratin-filled atrophic primary and secondary
spontaneous regrowth that often occurs on a hair follicles (witches feet) are suggestive of,
recurrent basis. Etiology and Pathophysiology but not pathognomonic for CRFA.
• The high incidence in some breeds and the • Biopsies may further support the diagnosis
Synonyms familial character of CRFA suggest a genetic but are not always performed if signalment
Canine recurrent flank alopecia (CRFA), canine influence. and characteristic lesions are seen.
idiopathic cyclic flank alopecia, cyclic follicular • The seasonal nature and annual recurrence
dysplasia, seasonal flank alopecia suggest that photoperiod may be involved. TREATMENT
The higher incidence of CRFA at higher
Epidemiology latitudes (around or north of the 45th paral- Treatment Overview
SPECIES, AGE, SEX lel in the Northern Hemisphere) supports The goal is to reduce or prevent hair loss.
• Dogs of both sexes, intact or neutered the implication of light exposure in this
• Age at onset of first episode: 8 months to disorder. Acute General Treatment
11 years (mean, 4 years) • Melatonin 3-6 mg/DOG PO q 8-12h for 1-2
DIAGNOSIS months may be beneficial in up to 50%-75%
GENETICS, BREED PREDISPOSITION of cases (whether initiated before or shortly
Boxers may account for about one-half of all Diagnostic Overview after the onset of alopecia).
cases, but other breeds at high risk include Diagnosis is based on history, clinical find- ○ To prevent hair loss, administer melatonin
English bulldog, Airedale terrier, and all sizes ings, and ruling out other differentials (e.g., 1-2 months before the expected episode
of schnauzers. Although CRFA seems to affect exclusion of concomitant hypothyroidism in of alopecia.
numerous breeds, the condition appears to dogs > 2 years of age). The rapid onset of well- ○ To shorten the duration of an existing
be rare to absent in the plush-coated Nordic demarcated truncal alopecia with spontaneous alopecic episode, start melatonin adminis-
breeds, German shepherds, and cocker spaniels. hair regrowth in predisposed breeds and the tration as soon as possible after the onset
absence of inflammation and pruritus make it of alopecia.
GEOGRAPHY AND SEASONALITY quite distinctive.
Characteristically, most dogs have an onset PROGNOSIS & OUTCOME
of alopecia between November and March Differential Diagnosis
(Northern Hemisphere). • Endocrinopathies (hypothyroidism, hyper- Dogs affected with CRFA are healthy otherwise,
adrenocorticism, hyperestrogenism) and benign neglect is a valuable therapeutic
Clinical Presentation • Other follicular dysplasias approach.
HISTORY, CHIEF COMPLAINT • Telogen defluxion
Fairly abrupt onset of bilateral alopecia affecting PEARLS & CONSIDERATIONS
the thoracolumbar region Initial Database
• Thyroid testing for adult dogs Comments
PHYSICAL EXAM FINDINGS • Other endocrine testing if indicated by The unpredictable course of CRFA and the
• Nonscarring alopecia, usually bilaterally history and physical exam findings spontaneous regrowth of hair render the
symmetrical, with well-demarcated borders
• Marked hyperpigmentation of the alopecic
skin is common.
• The alopecia is usually confined to the
dorsolateral thoracolumbar region, but
on rare occasions, the condition is seen in
association with alopecia on the dorsum of
the nose, base of the ears, base of tail, and
perineum.
• Spontaneous regrowth of a normal coat
occurs in 3-8 months (range, 1-14 months)
in most dogs.
• Most dogs develop recurrent alopecic
episodes every year, but some dogs have an
occasional year when the alopecia does not
recur.
• The degree of alopecia is variable, with some
dogs developing a virtually identical hair loss
(size and duration) year after year, and other
dogs developing larger areas and/or longer
episodes of hair loss as years go by.
• In a few cases, hair regrowth may become less RECURRENT FLANK ALOPECIA, DOG Recurrent flank alopecia in a boxer. Note characteristic distribution
complete after several episodes; it may even of alopecia and hyperpigmentation. (Copyright Dr. Manon Paradis.)

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