Head & Shoulders Helping Body Psoriasis

Hi there. At the start of the year I had some success treating my plaque psoriasis - which I have had for around 20yrs - by supplementing Vitamin D, after by chance it was discovered that I had a severe deficiency. The Vitamin D completely cleared my psoriasis until around May it came back with a vengeance. Scalp and body, mainly on arms, lower back, legs and scalp. Suddenly T-Gel which had always worked for my scalp psoriasis, suddenly wasn’t working at all. After being down about this for a while, I “borrowed” a family members Head & Shoulders as a last ditch attempt before trying to get an appointment with my derm. After one wash I noticed a difference to my scalp, nothing groundbreaking, but noticeable. I’ve been using it ever since and my scalp rapidly improved, but all of a sudden I noticed a change in the psoriasis on my arms, hands and legs, etc. Scales have cleared, and now noticeable clean skin patches are coming through the red patches. It’s slow, but I see an improvement everyday by just washing my hair. I’m moisturising with E45 cream on body, and Aveeno on my face. Has anyone else experienced anything similar, or does someone know what could be behind this?