All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
In the Hanafi school of jurisprudence, Imam Abu Hanifah’s opinion regarding blood coming from the nose is that if it is a small amount and does not flow into the soft part of the nose, then it does not invalidate Wudu (ablution). In al-Asl, Muhammad ibn al-Hasan ash-Shaybani stated: "I said, 'What do you think of a man who performs Wudu and then develops a nosebleed, which is a small amount that does not flow?' He (Abu Hanifah
) replied: 'It does not invalidate his Wudu.'" [End quote]
In al- Mabsut, Imam al-Sarakhsi explained the following statement 'If he develops a small amount of nosebleed that does not flow, his Wudu is not invalidated': What he meant is that this ruling applies if the blood remains in the hard part of his nose and does not flow into the soft part of it. [End quote]
Allah knows best.