Hello. Thank you for writing to us. It could very well be related to psoriasis. The salient features being that it is itchy at times and there is a positive history of psoriasis in your family. Moreover, history of trauma preceding the rash is significant and is a feature of psoriasis. This phenonmena is known as koebnerization. I suggest you to get it reviewed with a dermatologist. Psoriasis is fairly distinctive in appearance and classically affects extensor skin surfaces of legs e.g knee and shin. Psoriasis may involve other body sites as well and could be a clue to diagnosis. Scalp involvement with itchy scaly patches is commonly seen in psoriasis. If this turns up as psoriasis it would most likely be treated with topical potent steroid ointments with or without salicylic acid Or topical calcitriol/ calcipotriol with or without topical steroids. Topical emollients would help and you may use them frequently. Regards