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Endocrine Dermatoses. E. Simko WCVM. Endocrine dermatoses. Imbalances in hormones (excess or lack) More common in dogs Atrophic dermatoses with secondary pyoderma. E. Simko WCVM. Endocrine dermatoses. Non-pruritic, symmetrical alopecia Dry and dull hair coat Easily epilated hair
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Endocrine Dermatoses E. Simko WCVM
Endocrine dermatoses • Imbalances in hormones (excess or lack) • More common in dogs • Atrophic dermatoses with secondary pyoderma E. Simko WCVM
Endocrine dermatoses • 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 Hypothyroidism T3 T4 TRH TSH growth Primary: Lymphocytic thyroiditis - autoimmune dz Idiopathic thyroid necrosis and atrophy Secondary: Chronic diseases ( cortisol) E. Simko WCVM
Endocrine dermatoses - Hypothyroidism Changes • Over 6 years, cold intolerance • Hair coat dry, dull, coarse, sparse • Alopecia and adnexal atrophy • Dermal myxedema - tragic appearance • Abnormal reproduction • Secondary superficial pyoderma 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 Congenital Hypothyroidism 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 E. Simko WCVM
Endocrine diseases Adrenal gland Zona glomerulosa -- Aldosterone Zona fasciculata - Cortisol … Zona reticularis - Dihydroepiandrosterone Adrenal medulla Testosterone Estradiol E. Simko WCVM
Endocrine dermatoses Hyperadrenocorticism (Cushing's Disease) ACTH Cortisol CRH Hyperadrenocorticism • Pituitary (90% of dogs) • Adrenocortical (10-15% of dogs) • Iatrogenic E. Simko WCVM
Endocrine dermatoses - Hyperadrenocorticism Hepatomegaly Thin skin Inhibits activity of fibroblast Hepatic glycogen Alopecia Adnexal atrophy Cortisol Excess Immuno-suppression Collagen/elastin changes Collagen changes in blood walls Dystrophic calcification Abnormal hemostatis Infection E. Simko WCVM
Endocrine dermatoses - Hyperadrenocorticism Anti-inflammatory drugs Inflammatory response Histamine-dependent Antihistamines Platelet-dependent Eicosanoid PAF antag. Plasma-dependent Corticosteroids Antioxidants Phagocyte-dependent Cytokine antag. Antiproteinases Cyclosporin, etc Lymphocyte-dependent GF antagonists Growth-factor-dependent E. Simko WCVM
Endocrine dermatoses - Hyperadrenocorticism Diagnosis • Skin biopsies • Low-dose dexamethasone suppression test • High-dose dexamethasone suppression tests • ACTH stimulation test E. Simko WCVM
ACTH stimulation test (Specificity ~80%) 40 Cushing dz > 20 g/dl 30 Plasma cortisol (g/dl) 20 I/M ACTH Injection Normal6-17 g/dl 10 Iatrogenic Cushing’s or Addison’s dz 0 -1 0 1 2 Time (hour)
Low-dose dexamethasone suppression (%) 5 4 Cushing dz > 1 g/dl 3 Plasma cortisol (g/dl) I/M dexamethasone injection 2 1 Normal< 1 g/dl 0 -1 0 4 8 Time (hour)
High-dose dexamethasone suppression 5 Functional adrenal tumors> 1.5 g/dl 4 3 Plasma cortisol (g/dl) I/M dexamethasone injection 2 Pituitary dependent< 1.5 g/dl 1 0 -1 0 4 8 Time (hour)
Endocrine dermatoses Adrenal Neoplasms of Ferrets 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 E. Simko WCVM
Endocrine dermatoses Adrenal Neoplasms of Ferrets 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 E. Simko WCVM
Endocrine dermatoses - Adrenal neoplasms of ferrets Diagnosis: History Palpable perirenal mass Increased concentration of estradiol Curative response to adrenalectomy E. Simko WCVM
Endocrine dermatoses Hyperestrogenism 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