Reference: Duroos wa Fataawa al-Hajj – Volume 1, Page 19, No.29
Question: [Whilst in the state of ihraam] blood began dripping from my nose, so do I have to pay a penalty?
Response: If, whilst in the state of ihraam the pilgrim experiences blood flowing from his nose or the rest of his body, then this does not affect [the validity of] his state of ihraam.