Jennybay- What literally saved my life was the 5 Day Extended Patch Test, for Allergic Contact Dermatitis, ACD. My internal skin tingling, itching, taser like stinging was with me 24/7, but it felt worse at night because; 1. Histamines are higher at night. 2. Nothing to distract myself from the itch. I had neurological testing first, it felt like my nerves were the cause, but nothing showed up. The pain and itch inside the skin is something doctors can't see and therefore our credibility comes into question and yes I was close to losing my mind. Still my appearance was fine with no visible rashes (although on and off for 10 years previously did have hand rash eczema). Test results showed I reacted and was allergic to 5 out of 78 patch sites on the True Test ACD test and 3 were at the highest level. Turns out my 6 month old memory foam mattress, 90% of my clothing,all my shoes, flooring, 99% of cleaning and grooming products, one class of corticosteroid and an endless list more that contained my allergies were either in contact with me or off gassing (yes chemicals and elements can transfer through porous coverings and though your skin and into your bloodstream). I did not have the facial swelling you get, but steroid use either via shots or long term use with topicals can cause swelling and redness. In one form of eczema, Perioral which is a rash around the mouth, steroids which help for a brief period, then feed the eczema. My advice to you is, if not tested already, get in to see an allergist or dermatologist who is licensed to perform the 5 patch day patch test, my medicare paid for it and it is expensive without insurance. Check with office when making appt. to see if this doc is licensed for this test, not all are. Google this test, lots of information online. Also I take 3, 24 hr antihistamines a day, which seem to help with hay fever as I also have environmental allergies. Can't say they do anything with eczema itching issues as you have pointed out.
Your leg breakout after gardening does make me suspicious that it is a contact or allergic contact issue. For me I must only wear 100% cotton or 100% polyester clothing as blended materials contain an element from rubber MBT which I react severly to 1. So what is the fiber of your pants? What is your laundry powder, although you wash all your clothing probably with the same detergent, I am allergic to preservatives and fragrance so I must use special soaps. Even if I have fabrics safe for me, I cannot wash with other family members laundry if they have unsafe materials as the chemicals and allergic elements will transfer into my clothing. They do not wash out, it is called cross contamination. Not all forms of eczema can be prevented with contact control, however with ACD you can prevent future breakouts by controlling your contacts. I knew I was getting my face in trouble a few days ago as I was cutting back some perennials and dividing them and since one is on hands and knees the old flower heads brushed against my face, I did wash face off about 30 minutes later, but now have some itching and slight redness below one eye on lower lid. My fault, I did not control my contacts. Environmental allergies that cause asthma or hay fever have a different test, it's a simple 30 minute office visit prick test which tests for dogs, cats, pollen, dust mites, mold and so on. These issues are unrelated to my ACD allergies.
Your leg symptoms after garden are baffling, I do cover up with long sleeves and long pants and a broad brim hat. Of course I wear 100% cotton, what are the materials of your gardening clothes? I am sure it is the same laundry detergent as you use on other clothing that you don't react to. Are you pants loose, tight clothing will cause me to itch or get red? Is it possible pollen is transferring through your pants? I have immediate contact allergies to cedar and my yard is full of cedar trees. If I just brush against cedar or juniper I will get a rash, yet my denim has blocked that. I must wear a broad brim hat because if even one tiny bit of cedar drops off a tree and down my shirt I know within a few minutes as I can feel the itch.
I have had to learn a lot about eczema to get to where I am today, 95% great at this moment, sure symptoms will return, but I am prepared for it. I so hope you can get a name for what is tormenting you. Even being told you have a chronic disease with a name, at least can give you something visible to attack! Without a name it's an invisible tormentor and you can't direct your battle! Even if you don't test positive to anything on patch test, at least you can eliminate ACD issues and search elsewhere. Also if previously tested, remember our bodies change. 15 years ago I did not have ACD, if tested I would have not reacted. So if tested in the past, get retested.