The Prophet (ﷺ) allowed Az-Zubair and `Abdur-Rahman to wear silk because they were suffering from an itch.
Sahih al-Bukhari Book 77, Hadith 56
← Previous Hadith The Prophet (ﷺ) forbade us to use the red Mayathir and to use Al-Qassiy.

Sahih al-Bukhari Book 77, Hadith 55 Next Hadith → The Prophet (ﷺ) gave me a silk suit. I went out wearing it, but seeing the signs of anger on his face, I tore it and distributed it among my wives.

Sahih al-Bukhari Book 77, Hadith 57