Thanks for writing to us.
From the details provided she could be having lichen simplex chronicus(LSC).
LSC or neurodermatitis
can be primary which occurs without any cause and is seen as pigmented itchy hard plaques over easily accessible sites like hands arms or legs and nape of neck. These could be secondary too in response to any inciting factor like xerosis, eczema
, photo sensitivity etc.
Treatment requires oral antihistamine and use of potent steroid
with or without salicylic acid
Hope that helped.