Infections of the hand and forearm are a frequently seen surgical emergency of the hand. Patients of all age groups are affected and underlying systemic diseases are risk factors. Posttraumatic causes are the leading cause of infections. This includes cuts and stab wounds, animal and human bites but often also minor injuries. Due to the anatomical peculiarities of the hand, rapid progression of initially inconspicuous infections can occur resulting in functional limitations. If an infection is suspected, a symptom-oriented evaluation by a hand surgeon should be performed. This includes a detailed patient history, clinical examination, laboratory analyses and imaging. This is followed by the development of an individualized and interdisciplinary treatment concept with the aim of achieving the shortest possible rehabilitation period. The treatment includes surgical cleansing of the infection, accompanied by antibiotic treatment taking the expected possible spectrum of pathogens into account. Cephalosporins and aminopenicillins in combination with beta-lactamase inhibitors are the antibiotics of first choice. Follow-up treatment includes early functional exercise under the guidance of a hand therapist to minimize postinfectious restrictions in the range of motion and to enable occupational rehabilitation. In rare cases, fulminant necrotizing infections with resulting skin and soft tissue defects can occur. In these cases, secondary plastic reconstruction is usually required after cleansing of the infection.