The Laws of Arising in the Morning (22)

1. At a time when a person is learning, praying or eating, he should be very careful not to touch the covered parts of his body, and not to scratch his hair. If he did, he must wash his hands. (Shulchan Aruch and Mishne Berura 4)

2. A mourner may touch the uncovered parts in front of him and his neck and hands. If he normally walks barefoot, it is possible that even this is called one of the uncovered parts of the body, and if such a person touches his foot, he does not need to wash his hands. (Mishne Berurah ibid)