Before administering cefazolin (Ancef), the nurse checks for a previous allergic reaction to:

A. A Vitamin C deficiency:

While a Vitamin C deficiency can lead to oral health issues such as bleeding gums or scurvy, it is less likely to present with bright red oral mucous membranes and white patches. Vitamin C deficiency typically manifests with other symptoms such as fatigue, weakness, and joint pain.

B. Dehydration:

Dehydration can cause dry mouth and oral discomfort, but it is less likely to present with bright red oral mucous membranes and white patches. Dehydration may also result in a dry, sticky feeling in the mouth rather than soreness with white patches.

C. Poor oral hygiene:

Poor oral hygiene can lead to various oral health problems, including gingivitis and dental caries, but it is less likely to cause bright red oral mucous membranes with white patches. Poor oral hygiene typically results in plaque accumulation, gum inflammation, and dental decay rather than the specific symptoms described.

D. A superinfection:

This is the correct option. A superinfection occurs when opportunistic microorganisms, such as fungi or resistant bacteria, proliferate and cause infection following antibiotic therapy. Penicillin, like other antibiotics, can disrupt the normal balance of microorganisms in the mouth, allowing opportunistic pathogens to flourish and lead to conditions such as oral thrush (caused by Candida albicans) or oral candidiasis. The presence of bright red oral mucous membranes with white patches suggests the possibility of a superinfection, which warrants immediate attention from the primary care provider for further evaluation and management.

A. "Are you having any difficulty breathing?":

Difficulty breathing is a critical symptom that may indicate a severe allergic reaction, such as anaphylaxis, which can be life-threatening. It is essential to assess for difficulty breathing immediately as it requires urgent intervention to ensure the patient's airway is clear and to administer appropriate treatment.

B. "Have you noticed any blood in your stool?":

While blood in the stool could indicate gastrointestinal bleeding, it is not typically associated with allergic reactions to antibiotics. This symptom is more commonly associated with other conditions such as gastrointestinal ulcers, infections, or inflammatory bowel disease. While important to assess, it is not as immediately concerning as difficulty breathing in the context of a suspected allergic reaction.

C. "Are you having difficulty with your hearing?":

Difficulty with hearing is not a common symptom of allergic reactions to antibiotics. It may be associated with other conditions such as ear infections or ototoxicity from certain medications. While it is important to assess any changes in hearing, it is not typically an immediate concern in the context of a suspected allergic reaction.

D. "Do you have a headache?":

Headaches are a common symptom that can occur for various reasons, including stress, tension, dehydration, or as a side effect of medications. While headaches can sometimes occur as a side effect of certain drugs, they are not typically associated with severe allergic reactions such as anaphylaxis. Therefore, while it is important to assess for headaches, it is not as immediately concerning as difficulty breathing in the context of a suspected allergic reaction.