Skin: alopecia X

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Sections available in full article Introduction, Presenting signs, Age predisposition, Sex predisposition, Breed predisposition, Pathogenesis, Etiology, Predisposing factors, Pathophysiology, Timecourse (incubation, duration), Diagnosis, Presenting problems, Client history, Clinical signs, Diagnostic investigation, Confirmation of diagnosis, Histopathology findings, Differential diagnosis, Treatment, Initial symptomatic treatment, Standard treatment, Monitoring, Prevention, Control, Sequelae, Prognosis, Expected response to treatment, Reasons for treatment failure, Sources, Publications, Vetstream contributor(s),
Contributors Mr David Scarff BVetMed CertSAD MRCVS
Dr Rosanna Marsella DVM DipACVD
Prof Linda Frank MS DVM DACVD
Synonyms Adult onset growth hormon deficiency; adrenal sex hormone imbalance; hyposomatotropism in the mature dog; pseudocushings syndrome; congenital adrenal hyperplasia-like syndrome; castration responsive dermatosis

Introduction

  • Rare dermatosis, probably identified as 'growth hormone-responsive dermatosis' in the past. Also known as Adrenal sex hormone imbalance. However is now common in certain breeds, eg Pomeranians in the US.
  • Cause : unknown.
  • Signs : bilaterally symmetrical truncal alopecia often with hyperpigmentation of the skin.
  • Diagnosis : signs, histopathology, ruling out other endocrine diseases such as hypothyroidism and hypercortosolemia.
  • Treatment : neutering, if intact. Chemotherapy options include melatonin - mitotane, trilostane, or benign neglect.
  • Prognosis : good for health since this is a cosmetic disease but poor for permanent hair regrowth.

Diagnosis

Clinical signs

  • Symmetrical alopecia over frictional areas of tail, caudal thighs, ventral abdomen, cervical area and lateral trunk; head and extremities usually spared.
  • Coat color irregularly streaked.
  • Loss of primary hairs on trunk leaving 'fluffy' coat.
  • Retained secondary hairs lost slowly.
  • Hyperpigmentation in alopecic areas.
  • Tufts of hair regrow at sites of skin biopsy or trauma.
  • Perceived thin skin. Hairs contribute to thickness of skin and lack of hairs give a perceived thinness to dermis.

Diagnosis

Differential diagnosis

  • Other causes of symmetrical alopecia Skin: alopecia - overview especially endocrine disorders:
    • Hypothyroidism Hypothyroidism.
    • Hyperadrenocorticism Hyperadrenocorticism.
    • Setroli cell tumor Testicle: sertoli cell tumor.
    • Seasonal flank alopecia Skin: idiopathic cyclic flank alopecia.
  • Other causes of hyperpigmentation Skin: pigmentary disorders.

Sequelae

Prognosis

  • Good even if alopecia does not resolve, it is likely to remain the only clinical sign.
  • Guarded for hair regrowth.
  • In many cases side effects of treatment will be worse than disease.
  • Hair growth may commence within 10 days of castration.
  • Substantial hair regrowth within 3 months.
  • Some animals do not regrow all of coat.

Expected response to treatment

  • Hair regrowth should occur within 3 months of treatment but may take 6-9 months.
  • Response may be seen for months to years before alopecia recurs.

Reasons for treatment failure

  • Because the mechanism of the alopecia is not known, treatment success is seldom greater than 40% regardless of the treatment choice.
  • Individual variation in response to op'-DDD or other treatments.
  • Client non-compliance.
  • Misdiagnosis.

Sources

Publications

Refereed papers

  • Recent references from PubMed.
  • Frank L A, Donnell R L, Kania S A (2006) Oestrogen receptor evaluation in Pomeranian dogs with hair cycle arrest (Alopecia X) on melatonin supplementation. Vet Dermatol 17 , 252-258 PubMed.
  • Frank L A (2005) Growth hormone-responsive alopecia in dogs. JAVMA 226 , 1494-1497 PubMed.
  • Shibata K, Koie H, Nagata M (2005) Clinicopathologic and morphologic analysis of the adrenal gland in Pomeranians with non-illness alopecia. Jap J Vet Dermatol 11 ,115-120.
  • Cerundolo R, Lloyd D H, Persechino A, Evans H, Cauvin A (2004) Treatment of canine Alopecia X with trilostane. Vet Dermatol 15 (5), 285-293 PubMed.
  • Frank L A, Hnilica K A, Oliver J W (2004) Adrenal steroid hormone concentrations in dogs with hair cycle arrest (Alopecia X) before and during treatment with melatonin and mitotane. Vet Dermatol 15 , 278-284 PubMed.
  • Frank L A, Hnilica K A, Bohrbach B W, Oliver J W (2003) Retrospective evaluation of sex hormones and steroid hormone intermediates in dogs with alopecia. Vet Dermatol 14 , 91-97 PubMed.
  • Takada K, Kitamura H, Takiguchi M, Saito M, Hashimoto A (2002) Cloning of canine 21-hydroxylase gene and its polymorphic analysis as a candidate gene for congenital adrenal hyperplasia-like syndrome in Pomeranians. Res Vet Sci 73 , 159-163 PubMed.
  • Rijnberk A, Van Herpen H, Mol J A & Rutteman G R (1993) Disturbed release of growth hormone in mature dogs; a comparison with congenital GH deficiency. Vet Rec 133 , 542-545.
  • Schmeitzel L P (1990) Sex hormone-related and growth hormone-related alopecias. Vet Clin North Am Small Anim Pract 20 (6), 1579-1601 PubMed.
  • Schmeitzel L P & Lothrop C D (1990) Hormonal abnormalities in Pomeranians with growth hormone responsive dermatosis. JAVMA 197 , 1333-1341 PubMed.
  • Lothrop C D (1988) Pathophysiology of canine growth hormone responsive alopecia. Comp Cont Ed Pract Vet 10 , 1346-1349.
  • Scott D W & Walton D K (1986) Hyposomatotropism in the mature dog; a discussion of 22 cases. JAAHA 22 , 467-450.

Other sources of information

  • Frank L A (2009) Canine alopecia X. In: Hair Loss Disorders in Domestic Animals. L Mechlenburg, M Linek, DJ Tobin, eds.Wiley-Blackwell: Ames, Iowa, p. 148-155.
  • Schmeizel L P et al(1995) Congenital adrenal hyperplasia-like syndrome. In: Current Veterinary Therapy XII. Eds: Bonagura J D & Kirk R W. Philadelphia: W B Saunders Co.
  • Schmeizel L P & Parker W (1993) Growth hormone and sex hormone alopecia. In: Advances in Veterinary Dermatology - Volume 2.New York: Pergamon Press. Eds: Ihrke P J et al. pp 451.
  • Rosenkrantz W M and Griffin C E (1992) Lysodren therapy in suspect adrenal sex hormone dermatosis. Proceedings World Congress Veterinary Dermatology 2 , 121.
  • Rosser E J (1989) Castration responsive dermatosis in the dog. In: Advances in Veterinary Dermatology, Volume 1. Eds: von Tscharner C & Halliwell R E W. London: Bailliere Tindall.
  • Rosser E J (1987) Growth hormone-responsive dermatosis versus castration responsive dermatosis. Derm Dialogue.
  • Baker K (1986) Hormonal alopecia in dogs and cats. In Pract 8 (2), 71-78.

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