I'm so sorry your son has to go through this. I'm a pharmacy technician and a fellow sufferer. Since being diagnosed, I've familiarized myself with a lot of the treatments doctors use for this condition and have also developed a few habits that keep the condition largely in check.
Originally the blisters formed on the tops of my feet and between my toes, but strangely those have completely disappeared from my feet and now appear only on the sides of my fingers. (Affliction of the hand - in plain view for all to see and necessary to perform even the most rudimentary tasks - in my opinion - is much, much worse.)
When I was diagnosed I was in the miserable predicament of experiencing all 3 stages at once. Parts of my hands were covered in itchy blisters, other parts were covered with weeping red sores, and other parts were scaling and cracking. Not only was this physically unbearable; I was embarrassed and felt guilty, because I felt that I was ultimately responsible for not being able to control my scratching. At that time I was not even aware dyshidrotic ezcema existed, and had posed all sorts of frightening diagnoses (including the possibility I might have somehow contracted a form of herpes (there is a type that causes similar blisters.)) Anyone reading this who has not been diagnosed by a dermatologist - I urge you to see one. Even the bad ones know a lot about skin conditions, and in my opinion, paying the 100 or so dollars for a doctor's visit (even if you don't have health insurance) is worth the use of your hands or feet. It's possible that you have another condition, and dermatitis in general is finicky and ill-understood. If the people of the medical profession have trouble diagnosing it, you're at an even greater disadvantage.
My dermatologist diagnosed me before I was finished explaining my symptoms, explained the condition to me, gave me a cortisone shot (because I was in so bad a state) and sent me away with a prescriiption for a Class 1 (superpotent) topical steroid: Apexicon (Brand name: Psorcon E).
I found that I didn't even need the cream. The combination of the steroid shot and the relief of knowing what was wrong with me was enough to make the itching stop, and my hands healed completely in 3 weeks. Having normal hands again was such a joy!
It's summer now though, and it's been a humid 90 degrees all week and my fingers are a wreck. So finally, my advice:
1. Don't let your guard down. If your hands or feet are perfect, keep them that way. Moisturize every day after bathing or wetting the affected skin with something very mild and hypoallergenic. I've heard lots of people complain about the soaps and lotions their doctors prescribe/recommend, but I've never heard anyone complain about Cetaphil, and it's never irritated my skin. Take your soaps and lotions with you, and use them. Alcohol based hand sanitizers are not your friend.
2. If you notice blisters when they are tiny or just beginning, start applying your prescriiption cream immediately. They're not itchy yet, but they will be. If you don't have prescriiption cream, you could use hydrcoritsone cream 1 % over the counter. I would recommend against using ointment. It creates a barrier between your skin and the environment so no moisture can get in or out. I would continue my moisturizing regimen.
3. When those suc***s start to itch. Don't scratch. No really, don't scratch. Stick your hand in your armpit and count to twenty. Apply your corticosteroid and believe that it is working. This is the point at which you have control. Having been through the cycle at least once is reinforcement. Remember the weeping stage? Remember the painful cracking? Remember how horrible it looked? Don't let it get that way. No matter how satisfying it might be to wring your hands or scratch furiously at your feet, remember that the damage can last a month. Or longer! Don't hurt yourself. Don't risk infection, or the inability to walk or write. Don't scratch!
If it's too much a temptation, occlude it. I've found that gauze wrapped with tape is best at covering the strange shapes these blisters create, but if it's not available when the itching is most persistent, use a bandaid or put on a glove or a sock. But moisturize first and put on some anti-itch something. Because scratching through a band-aid or a glove or a sock or is even more abrasive and causes more damage to the skin than your hands or nails could. Sometimes I just stick my finger in my mouth. If you resort to this, don't bite! If you can, when the itch is most persistent and you feel like you can't resist, look at the affected area. Do you really want to scratch that? No! Don't!
NOTE: You should talk to your doctor about occluding (bandaging) the area if you continue to use a steroid cream. Covering that area can increase the absorption of the drug by up to 100% and that much steroid in your system, especially over a duration of time longer than 2 weeks, could be very bad for the rest of your body.
3. Oops, you scratched. Or the blisters opened on their own instead of drying out like a good blister should. Or you woke up realizing you had rubbed your hands or feet raw against the comforter. Or you slammed your hand in a car door. Someone in 6 inch high heels stepped on your toe. These things can and will happen. It's not your fault, but now you've got the weep. When serum is is oozing from the blisters, I find it's best to occlude it.
*Like I said before, if you're using corticosteroids, talk to your doctor. The skin on the tops of your hands and feet is very thin and absorbs more medicine than other parts of your body. If you wrap that area up, you absorb even more medication. And too much medicine can be bad. You want to stop the itch, not affect your adrenal cortex.*
The oozing can be messy. Stuff continuously coming out of your body and forming little pools on your hands or feet is disconcerting. Leaving drips on paperwork and having "wet" hands is embarrassing. "Wet feet" while wearing shoes is worse. This stage doesn't last long. Cover the affected areas while at work or out and about town, and give the area time to "air out" when you can be at home.
Don't scratch! At this point you already have the makings of an open sore. Don't make it bigger or deeper, even if new blisters are forming. At this point, if you are really itchy, make an appointment with your dermatologist. Because if you scratch... now...
4. Humongous open painful sore that is still itchy. Horrible combination. I find it's best to cover it up and let it breathe in cycles. Cover it for a while, uncover it until it starts to get itchy, cover it again and DON'T touch it. Eventually you'll be able to tell that your skin is healing. Because it's:
5. Scaling and Cracking. Best advice? Don't pick. Start moisturizing again. Give your skin what it needs. If it's dry, moisturize. If it's cracking and making a gaping red hole, use neosporin. Give it time to heal.
And if more blisters show up, leave them alone. The process will try to repeat itself. Don't let it.
I've found that stress really is a big factor for me and a lot of other people having this disease. Try to relax. This condition is genetic and aside from some lifestyle changes that might not have an effect on flare-ups, you can't stop it. But you can deal with it, and do your best to keep it under control. Minimize stress in your everyday life, and your entire body will benefit.