Which of the following is a common side effect of corticosteroid therapy?

Increased appetite is indeed a common side effect of corticosteroid therapy. Corticosteroids, such as prednisone, can influence various metabolic processes in the body, leading to heightened appetite and subsequent weight gain in some patients. This effect is due in part to changes in the neuroendocrine response, where the body's hunger signals may be heightened.

In contrast, hair loss, high fever, and skin rash are not typically associated with corticosteroid therapy. Hair loss may occur due to other factors, but it is not a classic side effect of corticosteroids. High fever usually indicates infection or another underlying condition, rather than a result of corticosteroid use. Skin rashes may be allergic reactions or unrelated issues, but they are not common side effects of corticosteroid treatment. Therefore, increased appetite remains the expected side effect among the options presented.