Alopecia X in a Pomeranian

24 Alopecia X in a Pomeranian

INITIAL PRESENTATION

Symmetrical, truncal, non-inflammatory alopecia in a Pomeranian.

INTRODUCTION

Symmetrical, truncal, non-inflammatory alopecia can occur for a number of different reasons, including follicular dysplasias and endocrinopathies. The most common endocrinopathies resulting in these symptoms are hypothyroidism and hyperadrenocorticism. There is a form of alopecia that occurs in plush-coated Nordic breeds characterized by bilaterally symmetrical, non-inflammatory alopecia with hyperpigmentation. The exact aetiology is not known and the condition has been designated ‘alopecia X’. This case report describes a case of alopecia X in a Pomeranian.

CASE PRESENTING SIGNS

A 4-year-old, spayed female Pomeranian was presented because of non-pruritic alopecia.

CASE HISTORY

The history in cases of alopecia X is of gradual, progressive onset of alopecia without systemic signs. There may be a history of hair regrowth over skin scrape, biopsy or other surgical sites.

The history in this case was as follows:

• There was a 12-month history of, initially, thinning of the hair coat over the dorsal neck, with later complete alopecia over the trunk but sparing the head and limbs.
• There had been no evidence of pruritus nor any evidence of inflammation.
• The areas of alopecia had become markedly pigmented.
• No polyuria, polydipsia or polyphagia, no weight change, no lethargy and no other signs suggestive of systemic involvement were seen.
• There was no regrowth of hair following 1 month of treatment with levothyroxine at a dosage of 10 μg/kg b.i.d.
• There was no regrowth of hair following 2 months of treatment with melatonin at a dosage of 2 mg t.i.d.
• A routine ovariohysterctomy had been performed after the onset of hair loss, and there had been hair regrowth over the spay wound site.
• There were six other related dogs within the household, none of whom had been affected, although the sire of the affected dog had developed similar symptoms that had remained undiagnosed.
• There was no zoonosis.
• The dog was fed a standard tinned dog food and biscuit mixer along with biscuits and dog chews.

CLINICAL EXAMINATION

There were no abnormalities on full physical examination.

The significant findings on examination of the skin were:

• Well-demarcated areas of partial to complete alopecia and hyperpigmentation over the trunk.
• The head and limbs were spared (Figs 24.1, 24.2 and 24.3).
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Figure 24.1 Hair loss on flank at presentation.

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Figure 24.2 Hair loss on flank at presentation (close-up).

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Figure 24.3 Hair loss on dorsum at presentation.

DIFFERENTIAL DIAGNOSES

The symptoms of symmetrical, non-inflammatory, truncal alopecia were supportive of a hair growth cycle disorder due to an endocrinopathy, although the differential diagnosis would include other causes of non-pruritic hair loss, including:

• Alopecia X
• Hypothyroidism
• Hyperadrenocorticism
• Seasonal or cyclical flank alopecia
• Telogen defluxion
• Sebaceous adenitis
• Alopecia areata
• Pseudopelade
• Demodicosis.

CASE WORK-UP

As with any case of alopecia, skin scrapes should be performed to rule out demodicosis. Routine haematological and biochemical examinations and further tests for hyperadrenocorticism and hypothyroidism were also indicated. In addition to a standard ACTH stimulation test measuring pre- and post-ACTH cortisol concentrations, the same test, measuring pre- and post-17-hydroxy-progesterone concentrations, has been used as an indicator of adrenal dysfunction. Post-ACTH 17-hydroxy-progesterone concentrations are frequently elevated in cases of alopecia X. Histopathological examination is unlikely to give a definitive diagnosis in a case of alopecia due to an endocrinopathy but would be helpful in ruling out other causes of hair loss.

The following diagnostic tests were performed:

• Microscopic examination of multiple deep skin scrapes showed no evidence of ectoparasitism.

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Alopecia X in a Pomeranian

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