[Acute rhinosinusitis in the adult patient].

Acute rhinosinusitis (ARS) is usually primarily a viral disease. During the course of the disease, bacteria can be detected by culture in about half of the cases. With a focus on the resulting treatment options, ARS is classified as acute viral RS (AVRS; duration < 10 days), acute post-viral RS (APVRS; worsening after approximately 5 days and/or duration > 10 days), and acute bacterial RS (ABRS; at least three of the following five criteria: fever > 38 °C, biphasic disease course, unilateral symptoms, severe pain, and elevated C‑reactive protein [CRP]). AVRS can be treated with zinc, decongestants, nonsteroidal anti-inflammatory drugs (NSAIDs), and phytotherapeutics. Intranasal steroids (INS) are additionally helpful for APVRS and antibiotics only for ABRS. The substance of first choice is amoxicillin; the potential benefit should be weighed against possible side effects and development of resistance in each individual case.