Hi, after suffering terribly for two years, i cleared my psoriasis using a juice fast. My body was 90% covered and i was virtually unable to walk, bend down etc. Ok, i lost three stone and looked dreadful, but the weight went back on. I juive fasted for six weeks and about a month after i finished, it cleared up. Im not advocating such a drastic idea for kids, but you should consider diet.
Avoid
Nightshades (aubergine, tomato, potatoe, red peppers
Processes foods, feed your daughter a clean a diet as possible. Replace sweets and crisps with dried fruit and nuts
Eat plenty strawberries and advocadoes
Sleep. Stress is a big link. I think mine was triggered by a traumatic birth.
Fresh carrot juice, also v cleansing.
Vitamin d drops. You can get this from amazon.
Apple cider vinegar can do an awful lot of good, make sure you get e organic stuff with the "mother".
Plenty waterand lemon, also v cleansing.
Topically, i ordered shea butter fron amazon. You can get a kilo of it (dont bother with the pretty wee boxes, you need the big plastic tub). Melt and rub in daily to the lesions, its amazingly healing.
Re conventional treatments, your choices are limited. I refused light treatment as we have a family history of skin cancer and im as white as can be. Steroids, coal tar and methoxotrate are all hard on the body, and methoxotrate is actually chemotherapy which really put me off. In my case, steriods just dampened down the symptoms for a couple of weeks, id keep a tube for big events if you need to look ok for a wedding, for example, but its a very short term solution.
I am pregnant now and can see bits of it coming back again, but my diet has been truly appalling; im not freaking about it though because I now exactly what to do to fix it and will get on with it as soon as i stop breastfeeding.
Good luck.