Most people have a fear of heights that are a little extreme for everyone. This includes tall observation decks that reach over 1000 feet in height or looking down in the grand canyon off a overhanging rock. This is a natural life instinct that senses danger.
Others have trouble dealing with being on top of a single story house 20 feet off the ground. This is more of an irrational fear than a life saving instinct. Perhaps they had a bad experience with heights when thy were a toddler.
A feeling of dizziness or vertigo is often felt when one is out of their natural element, such as being on the ground. A short climb up a ladder may induce feelings of nausea, increased heart beats, or even break out in sweats.
Hypnosis can be an effective way of dealing with these emotions. It is possible that the issue can be resolved within three or four sessions, depending on both the hypnotist and the client. This can be a life changing event for one with extreme fears.
Recordings and self-hypnosis can also be an efficient way of helping someone become free of past emotions which led to the phobia in the first place. If one of these methods do not work for you, perhaps a new technology such as brainwave entrainment or electromagnetic therapy might help. Seek out new ways and climb to new heights that you have never been before.