All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If you refer to vitiligo and not leprosy, then vitiligo is not among the diseases that are disgusting; it is for this reason that the scholars did not consider it among the diseases that give the spouse the choice to annul the marriage contract (in case he/she was not informed about it). Al-Mardaawi said: “As regards vitiligo, it is a change in the color of the skin, ….and it is not disgusting, so the spouse is not given the choice to annul the marriage contract.”
Moreover, this disease does not harm one’s health as stated by the specialists. Therefore, if this young man is religious and has a good moral conduct, then one should accept him as a husband for this girl. Abu Hurayrah narrated that the Prophet said: “If a man whose religion and moral character are pleasing to you proposes to you, then let him marry.” [At-Tirmithi] It might be that Allaah will bless this marriage and there will be much good in it.
Moreover, if that girl accepts him as a husband, then her guardian should not refuse him otherwise he is considered as preventing her from marriage without any sound reason. Al-Jalaal Al-Mahalli from the Shaafi’i School of jurisprudence, said: “Preventing the girl from marriage without a sound reason happens if an adult girl who has a sound mind wants to marry a suitable and competent man and her guardian refuses to marry her off.”
In case the guardian refuses to marry her off, then she should try to convince him in a soft and gentle manner. If he refuses to marry her off, then she has the right to take her matter to a Muslim judge (to marry her off).
The statement of Al-Mahalli continues as follows: “Preventing the woman from marriage without a sound reason should be confirmed to the Muslim judge so that he would marry her off, like if the guardian refuses to marry off the girl under his guardianship after he is ordered by the judge to do so.”
Allaah Knows best.