Narrated Anas (RA): The Prophet (ﷺ) used to say:

اَللَّهُمَّ إِنِّي أَعُوْذُ بِكَ مِنَ الْبَرَصِ وَالْجُنُوْنِ وَالْجُذَامِ وَمِنْ سَيِّئِ الْأَسْقَامِ

Allaahumma inni A‛oodhu bika minal-barasi wal-jununi wal-judhaami, wamin sayy'il-asqaam

O Allah, I seek refuge in Thee from leprosy, madness, elephantiasis, and evil diseases.

Reference: Sahih. Abu Dawud: 1554