E. Simko WCVM

Imbalances in hormones (excess or lack) More common in dogs Atrophic dermatoses with secondary pyoderma E. Simko WCVM

Non-pruritic, symmetrical alopecia Dry and dull hair coat Easily epilated hair Atrophy (catagen and/or telogen follicles) Hyperkeratosis Secondary pyoderma E. Simko WCVM

Endocrine dermatoses Lymphocytic thyroiditis - autoimmune dz Idiopathic thyroid necrosis and atrophy T3 T4 TRHTSH Primary: Secondary: Chronic diseases (  cortisol) E. Simko WCVM

Endocrine dermatoses - Hypothyroidism Over 6 years, cold intolerance Hair coat dry, dull, coarse, sparse Alopecia and adnexal atrophy Dermal myxedema - tragic appearance Abnormal reproduction Secondary superficial pyoderma Changes E. Simko WCVM

Endocrine dermatoses - Hypothyroidism Diagnosis Skin biopsies Old test: T4 & T3 concentration TSH stimulation New test: T4 & TSH concentration Auto-antibodies against T3 and T4 E. Simko WCVM

Endocrine dermatoses - Hypothyroidism E. Simko WCVM Large animals (Bo, Ov, Cap, Eq) Pathogenesis: maternal diets deficient in iodine or with goiterogenic substances genetic predisposition/defects Changes: Death or weak neonates with goiter Hypotrichosis with subcutaneous myxedema Suboptimal growth and skeletal development

Endocrine diseases E. Simko WCVM Zona glomerulosa -- Aldosterone Zona fasciculata - Cortisol … Zona reticularis - Dihydroepiandrosterone Adrenal medulla TestosteroneEstradiol

(Cushing's Disease) Cortisol CRH ACTH Hyperadrenocorticism Pituitary (90% of dogs) Adrenocortical (10-15% of dogs) Iatrogenic Endocrine dermatoses E. Simko WCVM

Adnexal atrophy Collagen changes in blood walls Collagen/elastin changes Infection Abnormal hemostatis Dystrophic calcification Immuno- suppression Alopecia Cortisol Excess Inhibits activity of fibroblast Thin skin Hepatic glycogen Hepatomegaly Endocrine dermatoses - Hyperadrenocorticism E. Simko WCVM

Anti-inflammatory drugs Endocrine dermatoses - Hyperadrenocorticism E. Simko WCVM Histamine-dependent Inflammatory response Platelet-dependent Plasma-dependent Phagocyte-dependent Lymphocyte-dependent Growth-factor-dependent Antihistamines Antioxidants Cyclosporin, etc Eicosanoid PAF antag. Antiproteinases Corticosteroids GF antagonists Cytokine antag.

Diagnosis Skin biopsies Low-dose dexamethasone suppression test High-dose dexamethasone suppression tests ACTH stimulation test Endocrine dermatoses - Hyperadrenocorticism E. Simko WCVM

ACTH stimulation test (Specificity ~80%) I/M ACTH Injection Time (hour) Plasma cortisol (  g/dl) Iatrogenic Cushing’s or Addison’s dz Normal 6-17  g/dl Cushing dz > 20  g/dl

I/M dexamethasone injection Time (hour) Plasma cortisol (  g/dl) Normal < 1  g/dl Cushing dz > 1  g/dl Low-dose dexamethasone suppression (%)

High-dose dexamethasone suppression Pituitary dependent < 1.5  g/dl Functional adrenal tumors > 1.5  g/dl I/M dexamethasone injection Time (hour) Plasma cortisol (  g/dl)

Changes: Polyuria & polydipsia Bilateral symmetrical alopecia Vulvar swelling Anemia and thrombocytopenia Pyometra and endometrial hyperplasia ~33% of affected ferrets have insulinomas Endocrine dermatoses E. Simko WCVM Neutred adult ferrets (mean 5 yr) Sex predilection

Changes: Polyuria & polydipsia Bilateral symmetrical alopecia Vulvar swelling Anemia and thrombocytopenia Pyometra and endometrial hyperplasia ~33% of affected ferrets have insulinomas Endocrine dermatoses E. Simko WCVM Neutred adult ferrets (mean 5 yr) Sex predilection

Endocrine dermatoses - Adrenal neoplasms of ferrets E. Simko WCVM Diagnosis: History Palpable perirenal mass Increased concentration of estradiol Curative response to adrenalectomy

Endocrine dermatoses Usual clinical presentation: Intact males and females over 6 years Males: Cryptorchid with estrogen-secreting tumor Feminization Females: Ovarian cyst/tumor – no estrus cycles Enlarged vulva Bilaterally symmetrical alopecia (esp. inguinal) E. Simko WCVM

Endocrine dermatoses - Hyperestrogenism Diagnosis : Skin and testicular/ovarian biopsies Serum estrogen levels Response to castration E. Simko WCVM