Ziyad related to me from Malik from Ibn Shihab that the Messengerof Allah, may Allah bless him and grant him peace, used to go torelieve himself in houses.Malik said, "Someone doing itikafshould not leave for his parents' funeral or for anything else."
USC-MSA web (English) reference: Book 19, Hadith 9
Arabic reference: Book 19, Hadith 699