How long does a cough last if you have laryngitis?

Depends: Everyone is different of course, but if treated appropriately, the cough should subside with the infection in 24-72 hours.

Weeks after primary : Though the primary infection, typically viral in nature, can last a few days, the damage from it can result in bronchospasm to mild stimuli such as cold air, resulting in bouts of severe dry coughing - this type of coughing can last. For weeks to several months.

If untreated,: It may last 2-3 weeks.