I can't really give you a diagnosis because I am not a doctor but I remembered that once my sister got something quite similar to what you have actually and she used a medication called Diprosone This is normally used for the relief of itching and acts as an anti-inflammatory.It can also be used for these treatments:

# An eruption of hard nodules in the skin accompanied by intense itching (prurigo nodularis)
# Area of thickened itchy skin caused by rubbing and scratching (lichen simplex)
# Eczema
# Inflammation of the skin
# Inflammatory skin disease known as discoid lupus erythematosus (DLE)
# Psoriasis
# Severe, widespread reddening of the skin (erythroderma)
# Skin disorder causing a flat, itchy, violet rash, usually on the wrists, shins, lower back and genitals (lichen planus)

Well, you must however not forget to asked your doctor first if you can take it.