Chickenpox is a common infectious disease caused by a virus that usually affects children. It is characterized by pimples on the body and is not serious in nature. In children, chickenpox can become secondarily infected, the pimples being at the heart of a bacterial infection: antibiotics treat this infection. When it occurs in adults, chickenpox can be responsible for severe pneumonia called varicella with cough, fever, and difficulty breathing. In immunocompromised adults, encephalitis can occur and has neurological consequences. Chickenpox is also a concern when it affects women in early pregnancy or just before delivery.