ENT complaints are common in primary care, yet their assessment can be challenging. Their clinical evaluation requires a knowledge of anatomy, pathology, and differential diagnoses. The boundaries between benign conditions and those requiring specific treatment or specialist referral is sometimes unclear. A structured clinical reasoning process, combined with a few key references, helps avoid the most common pitfalls. This illustrated practical guide is designed to support primary care physicians in providing safe, pragmatic, and guideline-based management. This first part deals with infectious diseases of the ear and tympanic membrane perforation.