Pediatric Collections offers what you need to know - original, focused research in a snapshot approach.The second part of this 2-part series on infectious disease, "Part 2: Indolent Head Scratchers," presents cases of patients not in imminent danger, but sick with puzzling symptoms and histories. Some of these cases have a prolonged clinical course, while others are just plain weird. Some cases present with common findings seen every day in clinical practice, but hide something rare and elusive under the surface, which comes into focus as the case progresses. Some of the diagnoses have been missed or overlooked for quite some time, given the indolent nature of the disease and cognitive biases.Similar to staring at an optical illusion for a long time, the frustratingly elusive diagnosis eventually comes into focus for each case. Together with "Part 1: Can't Miss Diagnoses," this series of infectious disease cases presents serious and puzzling cases designed to help you approach challenging patient cases with an open mind and bring pathogens and disease to light.