Hi, thanks for using healthcare magic
It is possible that it is related to eczema as suggested by your doctor,this would be associated with itching.
There is another condition called acanthosis nigricans
which is associated with darkening of the skin in the body folds. It normally involves the neck but can also affect other areas.
It usually occurs in persons over 40 and is most commonly associated with insulin resistance
. Insulin resistance means the body is resisting the effect of its own insulin and it is found in diabetes
, obesity and PCOS. Also with the use of medication such as steroids
that increase the insulin levels
Acanthosis nigricans can also be associated with abnormally level of thyroid
hormone and very rarely with more serious conditions.
Persons with acanthosis nigricans should be screened for diabetes so your mother may want to consider visiting her doctor for a screening test. In some cases other tests may be done to rule out other conditions.
Treating the cause results in some improvement of the skin.
i hope this helps