The invention provides methods and compositions for the prevention and treatment of Siglec-8 associated diseases such as chronic rhino sinusitis with concomitant asthma and aspirin-exacerbated respiratory disease. In particular, the invention provides methods for the prevention and treatment of Siglec-8 associated diseases through administration of antibodies or agonists that bind to human Siglec-8 or compositions comprising said antibodies or agonists. The invention also provides articles of manufacture or kits comprising antibodies or agonists that bind to human Siglec-8 for the prevention and treatment of Siglec-8 associated diseases such as chronic rhinosinusitis with concomitant asthma and aspirin-exacerbated respiratory disease.