Chickenpox is often thought of as just a benign children's disease, but chickenpox in children and adults, including pregnant women, can have devastating consequences. Chickenpox, a blistering rash, is caused by the varicella zoster virus and is highly contagious. Before the chickenpox vaccine was created, 4 million people caught the disease each year, and more than 80 percent of children had the disease by age 10. Complications of chickenpox occur most often in adults and small children but can happen at any age. Death, birth defects or permanent brain damage may occur.
Encephalitis
Encephalitis is inflammation of the brain and occurs in less than 1 in 1,000 cases of chickenpox, the Merck Manual states. Chickenpox encephalitis usually manifests symptoms toward the end of the acute disease period or within two weeks after the start of symptoms. While most people recover completely, permanent brain damage or death may occur. Signs of encephalitis include fever, severe headache, lethargy, drowsiness and confusion. Nausea, vomiting, stiff neck or back and seizures may occur. Personality changes, restlessness and hallucination may be part of encephalitis. In rare cases, the patient may go into a coma or have permanent learning disabilities. Treatment for encephalitis caused by chickenpox is intravenous or oral antiviral medications, to combat the viral infection, but are more effective if started early in the infection.
Pneumonia
Pneumonia complicates chickenpox more often in adults, people with immune problems and infants. Children without immune problems are less likely to develop pneumonia, the Merck Manual states. As many as 20 percent of adults with chickenpox develop pneumonia, the University of Maryland Medical Center reports. Symptoms of pneumonia include cough, difficulty breathing, shortness of breath, fever and malaise. While rare, people with pneumonia caused by chickenpox can die from the infection.
Bacterial Infection
The rash of chickenpox consists of as many as 300 to 500 clear blisters that break and then crust over. The blisters can become infected with bacteria, occasionally leading to a streptococcal group A infection known as "flesh eating bacteria." This is a serious, life threatening infection usually requiring intravenous antibiotics in the hospital.
Pregnancy Complications
Chickenpox during pregnancy affects mother and child. Up to 10 percent of pregnant women with chickenpox will have pneumonia. As many as one in 50 women who get chickenpox have a child with some type of birth defect, Children Hospital of Philadelphia states. Birth defects from chickenpox include limb malformations and mental retardation. Damage done to the fetus depends on the stage of pregnancy when the disease occurs. According to the National Health Service, babies whose mothers had chickenpox between weeks 13 and 30 of pregnancy had a less than 1 percent chance of having fetal varicella syndrome (FVS). Shortened limbs, scarring, eye problems such as congenital cataract and brain damage may occur. Chickenpox after 37 weeks increases the chance of preterm delivery; some babies are born with a severe case of chickenpox.
