- Kaposi Sarcoma (type of cancer)
- Kawasaki disease (pediatric blood vessel disease)
- Keloid (overgrown scar)
- Keratitis (inflammation of cornea)
- Keratosis pilaris (common skin condition)
- Kidney cancer (tumor)
- Kidney stone (nephrolithiasis)
- Klebsiella infection
- Knee laceration (skin cut)
- Knee ligament sprain
- Knee swelling