Final answer:
The priority finding in a toddler with gastroenteritis and signs of dehydration is Hypotension, which indicates a potential hypovolemic shock due to fluid losses and requires immediate treatment.
Step-by-step explanation:
A nurse assessing a toddler with gastroenteritis and signs of dehydration is likely to prioritize the findings in the order of the potential immediate threat to life. Among the options provided, Hypotension (B) is the priority finding because it indicates hypovolemic shock, which can be a direct consequence of fluid losses through vomiting or diarrhea in gastroenteritis. Hypotension in a dehydrated toddler is an immediate concern needing urgent treatment to restore circulation and prevent further deterioration.
While skin breakdown (A) is a concern due to prolonged exposure to moisture from diarrhea, it is not as immediately life-threatening as hypotension. Hyperpyrexia (C), a very high fever, and tachypnea (D), rapid breathing, are both important findings but are secondary to the immediate threat of hypotension.