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48 Amitraz Toxicosis

Differential Diagnosis ○ Skin scrapings PEARLS & CONSIDERATIONS
Symmetrical or diffuse alopecia with minimal ○ Minimum database: CBC, chemistry Comments
VetBooks.ir • Ectodermal defect or “normal” alopecic breed • Localized, multifocal, or inflammatory • Skin biopsies for alopecia: draw a fine, dark
profile, urinalysis
inflammation:
○ Thyroid testing
marker line along the direction of hair
• Hyperadrenocorticism (including iatrogenic)
• Hypothyroidism
the laboratory to section the biopsy along
○ Skin scrapings and other ectoparasite
• Hyperestrogenism (Sertoli cell tumor or other alopecia: growth, and center the biopsy over it. Ask
cause) detection techniques this line to obtain longitudinal sections of
• Alopecia X ○ Wood’s lamp examination and fungal the hair follicles. Collect several biopsies,
• Canine (recurrent) flank alopecia culture for dermatophytes and sample the most alopecic areas, partially
• CDA ○ Skin cytologic examination for bacteria alopecic areas, and normal skin.
• Breed-specific follicular dysplasia and Malassezia • In dogs, multifocal alopecia with concurrent
• Post-clipping alopecia ○ Trichography can help confirm traumatic inflammation is most commonly caused by
• Pattern alopecia hair fracture (self-trauma) or find Demodex bacterial folliculitis. Treat appropriately for
• Telogen (or anagen) effluvium mites, louse or Cheyletiella ova, and bacterial folliculitis, then re-evaluate.
• Pituitary dwarfism dermatophyte-infected hairs. • Skin scrapings are appropriate in almost all
Symmetrical or diffuse alopecia with cases.
inflammation: Advanced or Confirmatory Testing • Consider alopecia X in healthy, plush-coated
• Sebaceous adenitis • Symmetrical/diffuse alopecia with minimal or Arctic-breed dogs exhibiting truncal
• Leishmaniasis inflammation: alopecia.
Localized or multifocal alopecia: ○ Skin biopsies • Melatonin (3-6 mg/DOG PO q 12h for 3-4
• Bacterial (staphylococcal folliculitis): most ○ ACTH stimulation, low-dose dexa- months) is a safe and variably effective
common cause in dogs methasone suppression, or urine cortisol/ supplement to stimulate hair regrowth in
• Demodicosis creatinine ratio the treatment of various noninflammatory
• Dermatophytosis ○ Adrenal reproductive hormone panel is alopecic disorders.
• Malassezia dermatitis not commonly used. • Cyclosporine’s ability to stimulate hair growth
• Hypersensitivity dermatitis ○ Abdominal radiography/ultrasonography makes it useful for inflammatory, alopecic
• Pruritic ectoparasite infestation ○ Response to time (e.g., telogen effluvium) diseases such as sebaceous adenitis.
• Immune-mediated diseases (alopecia areata, or empirical therapy (e.g., melatonin) Technician Tips
pseudopelade, post-rabies vaccination pan- • Localized, multifocal, or inflammatory
niculitis and alopecia, dermatomyositis) alopecia: • Trichography (p. 1091) can be used in
• Other: epitheliotropic lymphoma, traction ○ Skin biopsies evaluating alopecic dogs, but normal anagen/
alopecia ○ Response to empirical therapy (e.g., telogen ratios are not established for most
See algorithm for canine alopecia (p. 1400). treatment for infection if bacterial follicu- breeds. The test is most useful for finding
litis is suspected) ectoparasites (particularly Demodex and louse
Initial Database ova), identifying hair shaft fracture, and
Appropriate testing depends on the differential TREATMENT finding large melanin clumps causing hair
diagnoses. shaft distortion in color-dilution alopecia
• Symmetrical/diffuse alopecia with minimal Treatment Overview and black hair follicular dysplasia.
inflammation: Correct underlying cause of alopecia. • Clients often ask about excessive shedding.
○ Trichography (microscopic examination of It is truly only excessive if alopecia results.
forcefully plucked hairs) can help identify PROGNOSIS & OUTCOME
demodicosis, CDA, black hair follicular SUGGESTED READING
dysplasia, dermatophytosis, telogen and • The prognosis for alopecia is good if the Paradis M: An approach to symmetrical alopecia in
anagen effluvium. Although trichography underlying cause of hair loss is identified the dog. In Jackson H, et al, editors: BSAVA Manual
is useful in some conditions, the proportion and treated and if hair follicles are still of canine and feline dermatology, ed 3, Gloucester,
of anagen to telogen hairs is highly breed present. UK, 2012, BSAVA, pp 91-102.
dependent. Except in nonshedding breeds • Extensive scarring and chronic ischemia limit AUTHOR: Kinga Gortel, DVM, MS, DACVD
(e.g., poodles), telogen hairs predominate. hair regrowth. EDITOR: Manon Paradis, DMV, MVSc, DACVD

Amitraz Toxicosis

BASIC INFORMATION characterized by sedation, ataxia, bradycardia, and more commonly used on dogs. Young, geriatric,
hyperglycemia. and small patients may also have increased
Definition sensitivity.
Amitraz is an acaricide that is an alpha-2 Synonym
adrenergic agonist. It is used for control Mitaban toxicosis GENETICS, BREED PREDISPOSITION
of mite, lice, and tick infestations in dogs Epidemiology No specific breed predispositions are known.
and several large-animal species. Amitraz-
impregnated collars and dips are available for SPECIES, AGE, SEX RISK FACTORS
tick prevention in dogs. Spot-on products Cats are more susceptible to toxic effects relative Topical exposure to large-animal formulations
were historically available. Toxicosis is to dogs, but amitraz-containing products are or incorrectly diluted small-animal products

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