A nurse is collecting data from a client who is breastfeeding and reports a sudden onset of chills and a tender, red area on the right breast. The nurse should identify that these manifestations indicate which of the following conditions?

A. Mastitis: Mastitis is an infection of the breast tissue, often caused by bacteria entering through a cracked nipple. It presents with localized redness, warmth, tenderness, swelling, and systemic symptoms such as fever and chills. These signs align with the client’s sudden onset of chills and a tender, red area on the breast, indicating an acute infectious process. B. Engorgement: Engorgement occurs when the breasts are overfilled with milk, leading to generalized swelling, firmness, and mild discomfort. It usually develops gradually rather than suddenly and is not associated with systemic symptoms like chills or fever. C. Blocked milk duct: A blocked duct can cause localized firmness and tenderness, often forming a small, palpable lump. Unlike mastitis, it typically does not produce systemic symptoms such as chills or fever, and the redness is usually limited to the area over the blockage rather than indicating infection. D. Thrush: Thrush is a fungal infection caused by Candida species, affecting the nipple or infant’s mouth. It presents with pain during breastfeeding, itching, or burning, and may show white patches on the nipple or tongue. Thrush does not cause localized redness, tenderness, or systemic symptoms such as chills.