What is the ruling on ablution if wiping the hair causes health problems such as dandruff and headaches?

Wiping the head is an obligatory act of ablution (wudu'), and ablution is not valid without it. Dandruff is not an excuse for omitting this obligation. However, it is permissible to wipe over the turban instead of the hair, as is the madhhab of the Hanbalis, provided that it is not removed after wiping until one prays. The duration for wiping over it is like the duration for wiping over the leather socks (khuffayn): one day and one night for a resident, and three days and nights for a traveler. The skullcap (taqiyyah) does not take the place of the turban for wiping.