A nurse is assessing a client who has a urinary tract infection and is taking sulfamethoxazole-trimethoprim. Which of the following findings should the nurse identify as a manifestation of an allergic reaction?

A. Insomnia: Insomnia is not a typical sign of an allergic reaction. It may occur as a nonspecific side effect of illness or other medications but is not indicative of hypersensitivity to sulfamethoxazole-trimethoprim. B. Photosensitivity: Photosensitivity is a known adverse effect of sulfamethoxazole-trimethoprim but is not an allergic reaction. It results in increased susceptibility to sunburn rather than an immune-mediated response. C. Hallucinations: Hallucinations are a rare neurologic side effect and are unrelated to allergic reactions. They may occur with severe systemic toxicity but are not typical of hypersensitivity. D. Wheezing: Wheezing indicates bronchospasm and airway involvement, which are classic signs of an allergic reaction. It reflects hypersensitivity and may progress to anaphylaxis, requiring immediate attention.