Canis ISSN: 2398-2942

Skin: alopecia X

Synonym(s): Adult onset growth hormon deficiency; adrenal sex hormone imbalance; hyposomatotropism in the mature dog; pseudocushings syndrome; congenital adrenal hyperplasia-like syndrome; castration responsive dermatosis

Contributor(s): David Scarff, Rosanna Marsella, Prof Linda Frank


  • 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.



  • Etiology is unknown.
  • Current research is focusing on genetics and hair follicle receptors.
  • It is likely that there is an inhibition of anagen initiation or prolongation which could be multifactorial.

Predisposing factors

  • Breed.


  • Poorly understood condition, etiology and pathogenesis not known.
  • Hormonal alterations reported could be normal for those breeds and may not reflect pathophysiology of the disease.
  • May be hair cycle arrest causing alopecia which coincidentally responds to GH supplementation. GH is a known stimulator of anagen.
  • The presence of mild hyperadrenocorticism might explain response to mitotane in some cases although response to mitotane does not generally correlate with cortisol concentrations.


  • Months to years.


This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login


This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login


This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login


This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading


Refereed papers

  • Recent references fromPubMed.
  • 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 Dermatol17, 252-258PubMed.
  • Frank L A (2005)Growth hormone-responsive alopecia in dogs.JAVMA226, 1494-1497PubMed.
  • Shibata K, Koie H, Nagata M (2005)Clinicopathologic and morphologic analysis of the adrenal gland in Pomeranians with non-illness alopecia.Jap J Vet Dermatol11,115-120.
  • Cerundolo R, Lloyd D H, Persechino A, Evans H, Cauvin A (2004)Treatment of canine Alopecia X with trilostane.Vet Dermatol15(5), 285-293PubMed.
  • 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 Dermatol15, 278-284PubMed.
  • 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 Dermatol14, 91-97PubMed.
  • 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 Sci73, 159-163PubMed.
  • 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 Rec133, 542-545.
  • Schmeitzel L P (1990)Sex hormone-related and growth hormone-related alopecias.Vet Clin North Am Small Anim Pract20(6), 1579-1601PubMed.
  • Schmeitzel L P & Lothrop C D (1990)Hormonal abnormalities in Pomeranians with growth hormone responsive dermatosis.JAVMA197, 1333-1341PubMed.
  • Lothrop C D (1988)Pathophysiology of canine growth hormone responsive alopecia.Comp Cont Ed Pract Vet10, 1346-1349.
  • Scott D W & Walton D K (1986)Hyposomatotropism in the mature dog; a discussion of 22 cases.JAAHA22, 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 Pet 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 Jet al. pp 451.
  • Rosenkrantz W M and Griffin C E (1992)Lysodren therapy in suspect adrenal sex hormone dermatosis.Proceedings World Congress Veterinary Dermatology2, 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 Pract8(2), 71-78.