A child displays increasing amounts of serosanguineous drainage from the left nares. What foreign body is the most likely cause?

The presence of serosanguineous drainage from the nares in this case suggests that there is irritation or injury occurring in the nasal passage. When a child has a foreign body, certain items can cause more pronounced symptoms due to their composition and what happens upon contact with mucosal tissues.

A button battery is particularly concerning because it can cause severe chemical burns and necrosis of the surrounding tissues. The electrochemical reaction between the battery and the moisture in the nasal cavity can lead to tissue damage, resulting in bleeding and fluid buildup, which presents as serosanguineous drainage. The risk of significant complications, such as penetration of the nasal tissue and potentially serious health consequences, makes this the most likely cause of the observed drainage.

Other foreign bodies can cause nasal obstruction and some form of drainage, but they are less likely to lead to a dynamic reaction that produces serosanguineous output in the same way that a button battery does. For instance, while a magnet can cause issues, it may not result in the same degree of irritation or chemical reaction within the tissues. A dried bean or fishing weight might also get lodged in the nasal passage, but they typically do not result in such acute injury or inflammation that would lead to the specific type of