Atrophic rhinitis, a chronic inflammation of the nasal mucosa leading to atrophy of nasal structures, is characterized by scanty mucus, greenish crusts, and a foul odor. The document discusses primary and secondary types of atrophic rhinitis, detailing various etiologies such as genetic factors, nutritional deficiencies, infections, and autoimmune responses. Treatment options include medical interventions like nasal douching and estrogen therapy, as well as various surgical procedures aimed at restoring nasal function and reducing symptoms.