Hello and welcome to HCM
You seem to have developed a chronic
allergic reaction or
eczema, or more likely
lichenoid dermatitis due to the dark color of patches.
Since you have the problem since a long time, and its recurring, you will need to keep an note of when the rashes and itching increase and decrease : such as weather changes, using any soaps,detergents, sun exposure, outdoor activity, any particular foods, any medicines like pain killers, antibiotics etc.
If you notice any such relation, you must avoid these factors.
Commonest causes on hands are detergents or foods, feet maybe due to footwear. The allergic reaction must have increased over the time to leave hard patches.
Similar rashes can appear on the head too. It can also be
dandruff.
You will have to
consult a dermatologist to rule out conditions like
psoriasis etc.
Do note that all these conditions take a long time to cure and can come back whenever you expose to an allergic factor.
Use a steroid+
salicylic acid ointment on the hard patches of feet and hands at night. Do not scratch or rub the area with rough objects.
Soak in warm water before applying.
During the day use a strong moisturizer like moisturex cream.
Take antihitamines like levocet daily for around 15 days till lesions start clearing and itching reduces. Dont use any harsh chemicals, soaps.
For scalp you can use Salisia-KT or similar shampoo twice a week.
Consult a dermatologist for exact diagnosis and further treatment and also testing of the skin can be done.
Hope this helps.