Why is Lupus not exempt from NHS Prescription Charges

Im just trawling the internet to try to find out where I can find a list of which illnesses are included or excluded in paying charges for prescription charges.

Im also thinking about paying a one-off fee which should cover me for charges and anything above what I have paid up front for will not be charged.

Very quickly I was staggered to find the following:

emption policy

[QUOTE]At present, some patients with chronic illness are exempt from patient charges if their condition is on a Department of Health list, originally drawn up in 1968, or if their income is below a certain level.

Patients with chronic illness can also pay £89 up front to cover the costs of their prescriptions over a year. [/QUOTE]

The £89.00 up front cover is Im sure out of date as the article was from 2002.
Im not so sure about the 1968 original list!.

I have a friend who has a thyroid problem and is exempt, even though it is an auto immune disease and a comfortable income.
I have a friend who has m.s who is not exempt, even though hers is also an autoimmune disease.

The lady with M.S is able to get a comfortable income from the government re benefits and never therefore has a lot of financial security and has recovered some of her ability.
Somebody else I know who seems worse off than her in some ways gets nothing and is financially unsecure.

Why do some auto immune diseases qualify and some do not re prescription charges.

I wonder where one goes to ask these questions to enable some change in the system.

Nicky