Sahih Muslim
The Book Pertaining to Clothes and Decoration (Kitab Al-Libas wal-Zinah)
Book Number: 024 / Hadith Number: 5170
Anas reported that Allah's Messenger (may peace be upon him) granted concession, or Zubair b. Awwam and 'Abd Al-Rahman b. Auf were granted concession, for the wearing of silk because of the itch that they both had.