Mayo Clinic Radio: Dermatology Your skin is not only the biggest organ in your body, it’s also the most visible. Dermatology focuses on problems with skin, hair and nails. Conditions range from acne and hair loss to skin cancer. Dermatologists diagnose and treat more than 3,000 conditions. Many dermatological conditions are treated with medication and noninvasive therapy, but some require more invasive treatment, such as surgery.