The Prophet ﷺ used to say, "O Allah, I seek refuge in You from insanity, leprosy, vitiligo, and evil diseases."
أخبرنا محمد بن المثنى قال حدثنا أبو داود قال حدثنا همام عن قتادة
أن النبي ﷺ كان يقول اللهم إني أعوذ بك من الجنون والجذام والبرص وسيئ الأسقام
[Its chain is daif] Abu Dawud narrated it in the Book of Prayer, chapter on seeking refuge, hadith 1554, from Qatada's narration through this chain, but I did not find an explicit statement that he heard it. It also appears in the Kubra, hadith 7929. Ibn Hibban graded it sahih, hadith 2446, 2447, and Hakim graded it as meeting the criteria of the two sheikhs, 1/530, and Dhahabi concurred with him.