A: Many doctors recommend that parents place a humidifier in their child's room when he's having difficulty sleeping due to congestion or croup, since the mist can help loosen congestion, reduce coughing and ease the child's breathing. The humidifier can be especially helpful if your home is particularly dry, such as during the winter.

Humidifiers disperse cool mist into the air, and vaporizers heat the water to disperse hot steam into the air. While cool mist and hot steam can both be helpful in reducing congestion, there are safety considerations. In general, pediatricians recommend cool mist humidifiers because the vaporizer's hot water and steam can burn young children if they put their face in the steam or tip the container over onto themselves. However, mold and bacteria can grow in the water in cool-mist humidifiers. This can be unhealthy to breathe, so it's important to follow the manufacturer's instructions regarding emptying the water and cleaning the container with soap and water daily, and disinfecting it weekly.

While it's generally safe to use a humidifier for short periods of time during an illness, using it continually can cause a moisture build-up on windowsills, in carpets and other surfaces. Excessive moisture promotes the growth of mold and dust mites, both of which can trigger allergies and asthma in susceptible people, and could make your grandson's congestion and cough worse. Opening doors to dry out the room can reduce the levels of moisture and molds.

Suggest to your grandson's parents that they talk with his doctor about determining the causes of his chronic croup symptoms and how to treat his condition most safely.