The most common childhood diseases include: Common Cold — It is called the common cold for a reason because it affects people of all ages, genders, and backgrounds. The common cold is typically not serious, however, its symptoms can range from mild to severe. Bronchitis and Bronchiolitis — Easily mistaken for the common cold due to the similarity of symptoms, bronchitis, and bronchiolitis frequently affect children. Stomach Flu (Gastroenteritis) — The stomach flu, typically caused by a bacterial or viral infection, can cause symptoms of diarrhea, vomiting, nausea, and fever in young ones. Hand, Foot, and Mouth Disease (HFMD) — A painful but not serious childhood disease, HFMD causes ulcers in or around the mouth, and on the hands and feet. Chickenpox — This viral disease is typically not harmful to children, however when present in adults, can be potentially life-threatening. Asthma — The most common chronic condition among children, asthma affects the lives of over 6 million children and adolescents in the United States. Allergic Rhinitis (Allergies) — Food allergies affect 1 in 13 US children, with even more affected by environmental and animal allergies.