Final answer:
Pyloric stenosis symptoms typically present in infants around 2 to 4 months old, with common signs including projectile vomiting, weight loss, and dehydration.
Step-by-step explanation:
The symptoms of pyloric stenosis commonly appear in infants, specifically within the age range of 2 to 4 months old. Pyloric stenosis is a condition where the opening from the stomach to the small intestine (pylorus) becomes narrowed due to thickening of the pyloric muscle. Early signs often include projectile vomiting, weight loss, and dehydration. As the stenosis worsens, the symptoms become more pronounced, making prompt diagnosis and treatment essential.