Which condition may cause dull skin or thinning of eyebrows?

Thyroid issues can significantly impact the skin and hair, making it the correct choice for conditions that may lead to dull skin or thinning of eyebrows. The thyroid gland plays a crucial role in regulating metabolism, and when it is underactive (hypothyroidism), it can lead to various skin and hair issues. Hypothyroidism may result in a decrease in the production of key hormones, leading to symptoms such as dry, dull skin and hair loss, including thinning eyebrows. This is due to the slowed metabolism affecting the body's ability to produce oils and moisture that keep the skin and hair healthy.

Anemia, while it can cause pale skin and fatigue, does not typically directly cause thinning of eyebrows. Dehydration might lead to dry skin, but it does not inherently cause changes in hair thickness or density. Diabetes can lead to various skin complications but is not primarily associated with dull skin or eyebrow thinning as the primary symptoms of the condition.