What is causing the inside of nostrils to be dry and crusty?

Dry and crusty nostrils can be caused by several factors, including low humidity, dehydration, and environmental irritants like dust or smoke. Allergies or sinus infections can also lead to inflammation and dryness in the nasal passages. Additionally, certain medications, especially decongestants, may dry out the mucous membranes. Maintaining proper hydration and using a humidifier can help alleviate these symptoms.