Which of the following symptoms would raise suspicion of chemical exposure?

Periorbital swelling and tightness in the throat are symptoms that strongly suggest chemical exposure, particularly in the context of allergic reactions or irritant effects associated with certain hazardous substances. This combination of symptoms indicates possible severe reactions to chemicals, such as those seen in exposure to specific agents (like gases or allergens), where swelling around the eyes (periorbital swelling) often suggests an inflammatory response. Tightness in the throat might indicate swelling that could obstruct the airway, a critical and urgent situation often linked with inhalation of toxic substances or severe allergic reactions.

In comparison, while the other symptoms can occur due to various medical conditions or exposures, they are more nonspecific. Elevated temperature and rash could indicate infection or allergic reactions but are not definitive for chemical exposure. Headache and nausea could arise from numerous causes, including viral illness or dehydration, without direct correlation to chemical exposure. Low blood pressure and dizziness may suggest shock or other medical emergencies without the direct indication of inhalation or contact with a chemical agent. Thus, the specific combination of periorbital swelling and throat tightness is a clear and concerning indicator of potential chemical exposure.