A patient who has been taking oral contraceptives reports to the clinic with complaints of left calf pain that worsens with activity. On assessment the nurse notices that the left calf is red and measures one inch larger than the right calf. Which condition should the nurse suspect?

A. Calf strain: A calf strain usually presents with localized pain and mild swelling after a known injury or overuse. It is less likely to cause significant redness, unilateral swelling of one inch, or progressive pain with activity without a precipitating trauma. B. Peripheral artery disease (PAD): PAD typically causes pain in the lower extremities with exertion (claudication) but is associated with cool, pale skin, diminished pulses, and hair loss, rather than redness, swelling, and unilateral calf enlargement. C. Deep vein thrombosis (DVT): DVT presents with unilateral calf pain, redness, swelling, and increased calf circumference. Oral contraceptive use is a known risk factor due to increased clotting tendency, making DVT the most likely condition in this patient. D. Cellulitis: Cellulitis presents with redness, warmth, and swelling, but it is usually associated with systemic symptoms such as fever and may not cause significant unilateral calf circumference changes. DVT should be ruled out first due to risk of pulmonary embolism.