Reference: http://mufti.af.org.sa/ar/content/حكم-الاغتسال-من-دواء-ليس-له-لون-ولا-رائحة
Question: I use ointment which has no colour nor smell on various parts of my body, and when I wake up from sleep, I pray the morning prayer without washing those parts of my body where I have applied this ointment. So is there any harm [in that], or does [using this ointment] nullify the wudhoo?
Response: If this ointment has no mass to it which would prevent water reaching the skin, then it is sufficient [when doing wudhoo] for you to wash those [required] parts of the body – and you are not required to do anything other than that.
If, however, this ointment prevents water reaching [the skin], then you are required [when doing wudhoo] to remove the ointment so the water can reach those [required] parts of the body.
If, however, removing the ointment or doing wudhoo is harmful to you, then in this case it is sufficient that you do wudhoo – as you would [in preparation] for the prayer – and leave those areas [where you have applied the ointment]. After you have finished [doing wudhoo, then with a dry hand] just wipe over (tayammum) those [required] parts of the body [on which you have applied the ointment].
