It is probably best to get a referral from your GP and see the ENT Specialist first as they will be able to schedule the appropriate audiological testing as well as undertake any other investigations that may be required. There may be some medical issue that can be resolved and longer term hearing management may not be required. If further hearing assistance is needed, you can see an audiologist and pursue this following the medical advice. There are a number of conditions that can cause a hearing loss in one ear to build up gradually including simple things such as ear wax and middle ear fluid - these can usually be medically- treated fairly quickly. In the case of wax build-up, as soon as it is removed the hearing usually returns to normal. Other conditions may take longer to treat or may not require medical intervention. The ENT specialist will be best placed to advise you on your individual case.