I want to know what is the difference between dementia and alzheimers?

Dementia is 1 kind: Most of the time when people say dementia, they mean alzheimer's. There are other less common forms of dementia. There is one that can happen from small strokes called vascular dementia. Another has memory issues, hallucinations, and parkinsonism called lewy body dementia. There is a very unusual one called frontotemporal dementia, and there are dementias from other causes such as infection.