What endocrine disorder does someone have if they experience dry skin and muscle cramps due to lack of thyroxine?

• A. Hyperthyroidism
• B. Hypothyroidism
• C. Cushing's syndrome
• D. Addison's disease

Answer: (B)

Low thyroxine lowers the body's metabolic rate, affecting many tissues. When thyroid hormone is deficient, the skin can become dry and rough because skin turnover and moisture regulation slow down. Muscles may cramp or feel weak as energy production in muscles decreases. This combination of dry skin and muscle cramps is characteristic of hypothyroidism, an insufficient thyroid hormone state. In contrast, too much thyroid hormone (hyperthyroidism) usually causes warm, moist skin, weight loss, and rapid heart rate. Cushing's syndrome involves excess cortisol with features like central obesity and thinning skin, while Addison's disease is adrenal insufficiency with fatigue, low blood pressure, and hyperpigmentation. Treatment typically involves replacing thyroid hormone to restore normal metabolism.