I've suffered on and off with blepharitis for many years. The pathology of the condition appears clear if my own situation can be considered typical, that it is a direct consequence of Meibomian gland dysfunction, leading to decreased/aberrant secretion from these glands (plus the occasional blockage of these glands leading to chalazia, thereby making the problem worse from irritation of the eye by the swollen mass) and an inflammatory reaction to antigens either deriving from deposited material itself or from bacterial growth in the material that deposits on the lids due to all these issues mentioned.
One interesting thing I might add to the information I have read in this forum is that this problem for me began during/following an Adenoviral infection in both eyes which persisted for a few months and led to thick yellow discharge that would appear dried and accumulated after waking up in the morning. A familiar pattern would be that this material would dry on the lid margins, then crack and lead to small lesions which became inflamed. Being only 18 at the time I hadn't the wisdom to know I had to clean it off diligently so that bacterial growth would not occur within this material and infect the lesions leading to lid margin swelling. I had no previous history of any sort of reddening of the lid margins or MGD before this point in my life. I think this persistent infection over several months sparked the condition and it has been a recurrent problem since unless managed properly. Since Adenoviral eye infections are relatively common, especially in adolescents, I would be interested in hearing whether anyone else recalls a similar infection sparking their problem(s). This connection may be of interest to clinical virologists/eye specialists who may not have previously linked the two conditions. I am a research virologist by trade myself and have never come across mention of this connection in the literature before. Nor do I have an interest in pursuing it academically!
Now, I have diligently tried a number of the standard treatments advised and here's my five pennies:
1. Cortisone creams: do work, and work well obviously. Only a temporary solution to the inflammation, not viable as a routine treatment and doesn't deal with the underlying condition in which blepharitis is allowed to occur.
2. Warm lid compresses: reduce the instance of chalazion formation for sure. I haven't had one since and I was getting a bad one once a year (that would persists for up to a year) on average before. They also appear to reduce blepharitis when used with my suggested product below. I wont say more about that since it's dealth with clearly and well in other sections of the forum.
3. Lid Scrubs: virtually cure the condition, well sorry that's an exaggeration it manages the condition, it cannot be cured per se. The actual product needs to be paid careful attention to though. I have tried many of the conventional treatments with detergent-based ones such as baby shampoo and, at least for me, even dilute detergent causes a slight but continual irritation of the eye for hours after thereby making the condition worse in the long run. What does work very well for me is to use something intended to be put near eyes or that the eye environment tolerates: women's eye make-up remover. Specifically I found 'L'Oreal dermo-expertise gentle eye make-up remover' works best and only costs 2 pound in the UK for a 125ml bottle (keep this closed when not used, it is essential everything you put near your eyes is clean). Simply apply a ml or two to a dense-knit, circular cotton wool pad (keep these as clean as possible or even sterile, reseal bag immediately after opening). Apply wet cotton wool pad along the lid margins both upper and lower taking great care not to get too much of it in your eye, in excess it can be irritating. For MGD sufferers (most people I think with recurrent blepheritis) pay careful attention cleaning the opening of these glands which are found between the region at the top of the lash margin and the point of the contact of the lid with the eye itself, keeping these openings clean (along with regular warm compresses, see above) is essential for avoiding chalazion formation and for helping reduce the overall blepharitis problem too.
Do this twice per day, once IMMEDIATELY after waking up because once you open your eyes the secretions that build up during the night settle properly on the lid margins to dry and once before going to bed. The longer the material is deposited on the lid margin, the more bacterial replication and therefore inflammation you get. Also do it if you feel a tingle of irritation which brings me onto the last point. Where possible do not touch your eyelids under any circumstances with less than soap-cleaned hands at any point. Learn proper aseptic technique and be mindful of where you are smearing dirty hands (with lots of nasty microorganisms) to your eyelids. This is a major contributing factor to the problem in my opinion.
Also, if you are just starting to do this you might find the problem gets worse for a few days, this is likely because you are further irritating already irritated lid margins, it takes a few days for the inflammation in the now clean area to settle down (cortisone cream would likely help at this early stage). Obviously if it's getting worse and stays worse after a week, stop using it as you might be allergic to something in it. Once it does settle down, you need to maintain this routine or the problem reoccurs. Remember it's managed not cured.
If I adhere to these rules, I don't get eyelid inflammation at all, if I slack I do. In life, you don't commonly get clearer proof of cause and effect than that!