Hi Dee
With most new conditions, the DWP applies the 'three-month rule' - that is, a claimant must have had it for the three months before they inform the DWP and the certainty that it will continue for the following 9 months. However, it is not just whether you have a new diagnosis - the issue is whether your health has deteriorated and whether you are looking for an improved award. If you were experiencing the symptoms before you got the diagnosis, and things have grown worse, you can put in for a change of circumstances to the DWP, in which case you will probably be sent a review form. Only do this if you think you meet the criteria for enhanced care, mobility or both.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems