Why is chicken pox more harmful to adults than to kids?

Get much sicker. Adults get sicker with high fever, more intense itching, and can get other infections such as pneumonia due to lowered immunity caused by the chicken pox. There's also greater risk of death, visible scarring, and shingles resulting from chicken pox in adults. It can also cause sterility in adult men. Adults immune system is stronger which is why they mount more of a response than kids.
Risk of complication. The reason for this is due to chickenpox related complications (usually from bacterial infections) which are more likely to occur in adults than in children. Although adults account for only 5% of chickenpox cases/year, they account for more deaths and hospitalizations compared to children.

Related Questions

Can adults catch chicken pox just like kids can?

Yes. If they never had them as a kid they can get them as an adult. Most (80%) who don't recall having them as a kid have blood test evidence that they did have them in the past. However, adult chickenpox is quite worrisome with some developing a fatal pneumonia and many quite sick with the illness.

Can you get chicken pox as a child and then again as an adult?

Very Rarely. If you truly had chicken pox as a child, it is very, very unusual to have them again as an adult. Probably possible, but not likely. Shingles does commonly occur as an adult after childhood exposure.

What are the adult symptoms of chicken pox that children might not get?

Varicella. The major complications from chicken pox in adults are : bacterial skin infection, nerve irritation, pneumonia and hepatitis. Although these can occur in children, adults who get chickenpox have even higher rates of complications.

Why is it more dangerous to get chicken pox as an adult than to get it as a child?

Chicken Pox in adult. It is a miserable condition when you have it as a kid, and it is worse as an adult. The chances of getting varicella pneumonia increase when chicken pox occurs in adults, and you definitely don't want that. If you suspect you have it, see your dermatologist or pcp for treatment as soon as possible. If you didn't have chicken pox as a child, consider both varivax and zostavax as well.
Pneomonia. Vericella pneumonia is a life theatening risk for an adult who develops chicken pox. The adult needs to be started on antiviral medications as soon as possible.

Is having chicken pox as an adult truly more dangerous than getting chicken pox as a child?

Adult chicken pox. Chickenpox complications are more likely to occur in adults than in children. Despite the fact that adults account for only 5 percent of chickenpox cases per year, they account for a disproportionate number of deaths (55 percent) and hospitalizations (33 percent) compared to children.

Does chicken pox in young children always cause shingles later as an adult?

See below. Shingles is the reappearance of the chicken pox virus in adulthood after a period of stress or immunocompromise. You must have had chickenpox earlier in life to develop shingles.
Will not trigger it. The exposure to a child with chickenpox will not cause shingles to appear in an adult. If the adult never had chickenpox (rare) it could be passed to the adult as the generalized illness of chickenpox. Incubation period would be 10-21 days (ave 14).

I'm wondering why are adults more likely to get pneumonia from chicken pox (varicella pneumonia) than children are?

Because. Many illnesses that are mild when they occur in childhood are more more severe when contracted as an adult. It may be that the immune response is over-reactive in the adult organism & that this hyper-response is at least partially responsible for the severity of symptoms in adults. Mononucleosus is typically worse when occurring in adults and adolescent. In younger children its just like a cold.
Chicken pox. Varicella is contagious and is trransmitted by coughing. The infected person will get sick a week later and develop a skin eruption with tiny blisters. Varicella occurs mostly in children, who rarely get pneumonia. Adults rarely get varicella at all since they are immune from their childhood infection. Those with immune disorders, . Hiv or leukemia, are often sicker and may get pneumonia.