The doctor is right saying that it is due to dry skin.
Dry skin leads to itching which can be troublesome.
Medications do help but applying a moisturiser everyday even if the problem is solved is must to avoid the problem from coming back.
Next Steps
Hot water showers, Sitting in A/c for long does trigger this problem. Also check for
thyroid profile.
Health Tips
Have bath with lukewarm water, bathing time should be cut short not more than 5-7 minutes. Donor rub your skin with towel just dab it. When the skin is little moist after bath apply a moisturising lotion to seal the already present moisturiser