Hello,
There are many possibilities which can cause such dry skin on the penis head. It can be due to atopic dermatitis, eczema , harsh chemicals that aggravate the skin condition on your penis, psoriasis or erythroplasia or querat( skin malignancy which presents as redness, scaling and crusting).
I suggest you to get it evaluated from a dermatologist and get the biopsy done.
I hope it helps. Take care and regards.