A: Children's colds are caused by viruses and go away on their own within a week or two. The basic treatment is to make sure your child gets plenty of rest and fluids. But if your child has problems sleeping due to congestion and coughing at night, increasing the moisture in the air can sometimes help. Moisture helps loosen up and drain the congested mucus in the nose, and decrease swelling in the nasal passages, opening up the airways for breathing. Added moisture is especially helpful if the air in your home is particularly dry. Steam does not actually attack the viruses causing the cold.

The basic difference between humidifiers and vaporizers is that humidifiers disperse cool mist into the air, and vaporizers heat the water to disperse hot steam. While cool mist and hot steam can both be helpful in reducing the congestion of colds, there are some other safety considerations to be aware of. 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 on themselves. However, cool-mist humidifiers can grow mold and bacteria in the water, which can be unhealthy to breathe, so it's important to follow the manufacturer's instructions to empty the water and clean the container with soap and water daily.

While it's generally safe to use a humidifier when your child has a cold, this should not automatically be done if your child has asthma. Moisture in the air can promote the growth of mold in carpets and other surfaces, and mold can make children's asthma symptoms worse. If your child has asthma, discuss with your doctor whether a humidifier would be helpful or not.