@Thatone5
Yes! I was very very lucky to get it on the NHS after I ended up taking the max dose allowable of fexofenadine plus still taking over the counter anti-histamines.
I was utterly miserable. As you say you get zero relief! My asthma was constantly triggered. My sinuses were inflamed 24/7 (that was the worst part of it constant headache every day). My lips and eyes swelled up and I applied allergy cream like a moisturiser. I was on cortisteroid nasal sprays. Nothing helped. I had to get a job working outside, as I couldn't work anywhere enclosed with carpets or rubbish air conditioning. I ended up carrying an epipen for reassurance in case my throat swelled up.
I couldn't walk into a bookshop, a library or any clothing/carpet/charity/furniture store without being triggered and my throat feeling like it was closing up. I couldn't sleep in my bed even with anti-dustmite covers on. I couldn't sleep in hotel rooms with carpets. I couldn't open my wardrobe without sneezing. I couldn't accept offers for sleepovers or visits with friends without having to think about what their house was like as I couldnt manage the environment. In fact I didn't sleep over.
I went on holiday to New York and it was hell in the hotel room which was carpeted even along the walls. I hadn't thought about the room beforehand, my reaction was so bad I had to spend the first day looking for a pharmacist for some extra meds.
I had to beg my doctor to consider recommending me as it was taking over my life. When I went for the consultation they measure me and said 'oh most people have some dust mite allergy and your skin prick test indicates a reaction but not a severe reaction' I had to tell them exactly in detail how it was affecting my life in every way. After that they green lighted me. So note. The skin prick test doesn't always correlate with how severely your immune system is over reaction in terms of effects.
Thankfully, it has worked for me. It didn't start working till end of 2nd year though. Note it does not get rid of it completely, it is not a 'cure' and they say it will only last a certain amount of years. But it calms down the response. I still can't tolerate carpets or dusty places for too long. Travelling on the Tube will still leave me really stuffy. My bed is still a bit of a problem, but I alternate between the sofa (which is a sort of faux leather) and the bed. But I have a life and only take otc meds occasionally now. I can also shop without being triggered (yay) as clothes shopping had become hell. I am also back to being a housework slattern!
It is worth pushing hard for. I say do it! Dust mite allergy is so overlooked in comparison to peanut (obviously peanut allergy can kill you) but when it becomes really aggressive you have zero life, because it is 24/7 whereas with other allergies you can often limit your exposure.
Tell your doctor every way it is affecting you, because it is true most people have DM allergy but it is a nuisance rather than a real problem so a doctor may not understand that when it becomes very bad it takes over your life!
And I hope this helps. I know the misery. PM if you want to ask any questions.