Data from Asthma UK show that emergency admissions for asthma vary from 175% above the national average to 58% below.
Variations also exist across large regions. People in the north west are twice as likely to be admitted to hospital for asthma as people in the east of England.
Up to £4.5m could be saved if PCTs with high rates reduced admissions to the national average, Asthma UK estimates.
Neil Churchill, chief executive of Asthma UK said the charity was working closely with PCTs to help them reduce their rates.
'We recognise this is a big challenge for PCTs but changes like providing access to local specialist asthma nurses and offering every person with asthma a personal asthma action plan will make a big difference in ensuring effective asthma management,' he said.
'Having an asthma chapter in the forthcoming COPD national strategy in England and the forthcoming asthma standards in Northern Ireland will also aid healthcare professionals and we look forward to working more closely with the governments and health services across the UK to maximise the chapter's impact'.