Varicella is a particular problem in hospitals when there are patients with immune systems weakened by drugs (e.g., high-dose steroids) or HIV.Secondary bacterial infection of skin lesions, manifesting as impetigo, cellulitis, and erysipelas, is the most common complication in healthy children. Disseminated primary varicella infection usually seen in the immunocompromised may have high morbidity. Ninety percent of cases of varicella pneumonia occur in the adult population. Rarer complications of disseminated chickenpox include myocarditis, hepatitis, and glomerulonephritis.Hemorrhagic complications are more common in the immunocompromised or immunosuppressed populations, although healthy children and adults have been affected. Five major clinical syndromes have been described: febrile purpura, malignant chickenpox with purpura, postinfectious purpura, purpura fulminans, and anaphylactoid purpura. These syndromes have variable courses, with febrile purpura being the most benign of the syndromes and having an uncomplicated outcome. In contrast, malignant chickenpox with purpura is a grave clinical condition that has a mortality rate of greater than 70%. The cause of these hemorrhagic chickenpox syndromes is not known. Epidemiology
Primary varicella occurs in all countries worldwide. In 2015 chickenpox resulted in 6,400 deaths globally – down from 8,900 in 1990. There were 7,000 deaths in 2013. Varicella is highly transmissible, with an infection rate of 90% in close contacts.In temperate countries, chickenpox is primarily a disease of children, with most cases occurring during the winter and spring, most likely due to school contact.
Varicella zoster can affect the arteries in the neck and head, producing stroke, either during childhood, or after a latency period of many years. Shingles
After a chickenpox infection, the virus remains dormant in the bodys nerve tissues for about 50 years. This, however, does not mean that VZV cannot be contracted later in life. The immune system usually keeps the virus at bay, however it can still manifest itself at any given age between 1 and 60, causing a different form of the viral infection called shingles (also known as herpes zoster). Since the human immune system efficacy decreases with age, the United States Advisory Committee on Immunization Practices (ACIP) suggests that every adult over the age of 50 years get the herpes zoster vaccine.Shingles affects one in five adults infected with chickenpox as children, especially those who are immune-suppressed, particularly from cancer, HIV, or other conditions. Stress can bring on shingles as well, although scientists are still researching the connection. Adults over the age of 60 who had chickenpox but not shingles are the most prone age demographic. Diagnosis
The diagnosis of chickenpox is primarily based on the signs and symptoms, with typical early symptoms followed by a characteristic rash. Confirmation of the diagnosis is by examination of the fluid within the vesicles of the rash, or by testing blood for evidence of an acute immunologic response.Vesicular fluid can be examined with a Tzanck smear, or by testing for direct fluorescent antibody.