Which of the following is a clinical sign of oleander toxicity?

In cases of oleander toxicity, one of the clinical signs that may be observed is cold extremities. Oleander (Nerium oleander) is a highly toxic plant that contains compounds such as cardiac glycosides, which can have profound effects on the cardiovascular system. This can lead to poor circulation and lower body temperatures in the extremities due to the body's compromised ability to maintain normal blood flow.

Cold extremities indicate that the body is not properly regulating its temperature and blood flow, which aligns with the physiological disruptions caused by oleander toxicity. This symptom, along with others such as gastrointestinal upset or cardiac arrhythmias, can be indicative of severe exposure to the toxin.

The other signs listed, while they might occur in other types of poisoning or medical conditions, are not specifically associated with oleander toxicity. Coughing could be related to various respiratory issues, fever is typically a sign of infection or inflammation rather than direct toxin exposure, and hair loss is generally not a symptom of acute poisoning but may indicate chronic conditions or nutritional deficiencies. Thus, cold extremities is the most relevant clinical sign in the context of oleander toxicity.