Is it permissible to wipe the bottom of the feet during Wudu' due to eczema that is affected by water?

It is permissible to wipe over a painful area if washing it would harm the foot, and tayammum (dry ablution) is not necessary. If the wound is exposed, washing it is obligatory; if that is not possible, then wiping; and if that is not possible, then tayammum. If it is covered, then only wiping is permissible. If wiping, even while it is covered, would cause harm, then one resorts to tayammum. It is also permissible to take the concession of wiping over leather socks (khuffayn) or regular socks (jawrabayn) after a complete water ablution.