Muwatta Malik · Hadith 78

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَبْدَ اللَّهِ بْنَ عَبَّاسٍ، كَانَ يَرْعُفُ فَيَخْرُجُ فَيَغْسِلُ الدَّمَ عَنْهُ ثُمَّ يَرْجِعُ فَيَبْنِي عَلَى مَا قَدْ صَلَّى ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Abbas used to have nose-bleeds and would leave to wash off the blood. He would then return and complete his prayer

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).