Diffuse Alopecia and Thyroid Atrophy in Sheep

Abstract

Thyroid dysfunction substantially affects the quality of life due to its association with various disorders in different organs. A low intake of selenium and zinc can predispose to thyroid alterations, resulting in hypothyroidism. A deficiency of selenium and zinc causes direct and indirect skin lesions, both by the action of free radicals on the skin and by thyroid dysfunction. The aim of this study was to describe natural cases of diffuse alopecia and thyroid abnormalities in sheep with selenium and zinc deficiency. Five adult sheep presented marked and diffuse alopecia, and the residual hairs were dry and brittle. The skin was thick and crusty, with marked peeling. The triiodothyronine (T3) and thyroxine (T4) serum concentrations were below reference values for the species. Zinc and Se concentrations were low in both the serum and liver. During necropsy, cachexia associated with serous fat atrophy was observed, and the thyroid glands showed marked atrophy. Microscopically, the thyroid presented multifocal to coalescent atrophy, with atrophied and dilated follicles, macrophage infiltration, and the presence of fibrous connective tissue. The skin revealed hyperkeratosis and edema. It is concluded that thyroid atrophy, alopecia, and hyperkeratosis are associated with low serum and liver concentrations of zinc and selenium in sheep.

Association between Alopecia Areata and Thyroid Dysfunction

“…In a recent study from Brazil concluded that severe alopecia and fibrosis and atrophy with thyroid deficiency is associated with zinc and selenium deficiency in sheep. The researchers also noticed that deficiency of these two elements is associated with hypothyroidism and that addition of zinc and selenium improve thyroid function both in animals and humans [11].…”

Editorial: Community series in the mechanism of trace elements on regulating immunity in prevention and control of human and animal diseases, volume II

“…Thus for this, a lack of selenium-induced liver circulation disorders or immune stress are also associated with heart failure and downregulation of splenic cell proliferation ( 25 , 26 ). In addition, selenium can indirectly cause thyroid atrophy, alopecia, and keratosis in goats by affecting the activation of macrophages in the liver ( 27 ). Mechanically, researcher found that the protective effects of selenium on liver are possibly attributed to the upregulation of antioxidant enzyme activity in macrophages and the inhibition of inflammatory factor secretion ( 28 ).…”