Persistent bed-wetting after age five in the absence of urologic, medical, or psychiatric pathology is considered a primary enuretic disorder. Typically, the child has never achieved continuous dry nights. Enurectic episodes occur throughout all sleep stages, as well as during nocturnal awakenings.

The majority of episodes occur in the first third of the night. Bladder control during the daytime can be normal. It is continuous from infancy, with children wetting from once or twice a week to nightly. Small functional bladder capacity and an irritable bladder are associated with multiple wettings at night and also with increased frequency of voiding and urgency during the day.

Dreaming is vaguely and infrequently reported in conjunction with bed-wetting, particularly when it occurs in the first hours of the night. Typically, the sleeper dreams of being in the bathroom. Such dreams are initiated after the onset of micturition and are not precipitating events.

Obstructive breathing and sleep apnea may be precipitating factors, particularly in children who have loud snoring. When obstructive sleep apnea syndrome is diagnosed, both the apnea and the enuresis often resolve after treatment of the apnea. Allergies may play a role in the perseverance of enuresis. Some children with the disorder have been shown to be allergic to milk products and to suffer bladder irritability.