Which symptom is most likely to suggest the presence of thrush in an infant?

The presence of white patches in the mouth is a classic symptom of oral thrush, which is a fungal infection caused by an overgrowth of Candida species. In infants, these white patches typically appear on the tongue, inner cheeks, and gums, and they may look like cottage cheese. This symptom is significant because the patches can sometimes be scraped off, revealing a red, inflamed surface underneath. The distinctive appearance of these patches helps differentiate thrush from other conditions that may cause similar oral symptoms.

The other symptoms listed do not specifically indicate thrush. High fever may suggest a variety of infections but is not characteristic of thrush. Green stool can occur for many reasons, including dietary factors or gastrointestinal infections, and does not point specifically to thrush. Coughing fits could be related to respiratory conditions or allergies but are not indicative of a fungal infection like thrush. Thus, the presence of white patches is the most reliable indicator of thrush in an infant.