As a complicating factor, several different internal diseases may induce the same cutaneous change. Some skin changes may be more suggestive of certain types of internal disease. Cutaneous manifestations may be a marker of a pathologic process, but not a specific disease. Hormones regulate physiologic processes in the body. Excesses or deficiencies result in quantitative changes in morphology or function.
Cutaneous changes resulting from endocrine imbalance occur as a result of the following mechanisms.
First, the skin may respond as a target organ, with different hormones having effects on specific areas of the skin. The target areas include all elements of the skin, including the epidermis, melanocytes, pilosebaceous units, dermal elements, adipose tissue, the cutaneous immune system, and endothelial cells. For example, growth hormone deficiency results in decreased amounts of dermal elastin, decreased thyroid hormone levels lead to pilosebaceous atrophy, and excessive glucocorticoid levels result in epidermal and dermal atrophy. Second, hormonal excesses or deficiencies may effect various metabolic functions that may indirectly influence the structure and function of the skin. Pinnal erythema may be associated with increase blood flow in hyperthyroid cats, xanthomas with dyslipoproteinemias, and calcinosis cutis with hyperadrenocorticism or hypervitaminosis D. Immunologic effects of hormonal disturbances are also responsible for many cutaneous lesions.