Patient Portal Patient Portal at Preferred Dermatology Access your health information securely with the Patient Portal at Preferred Dermatology. Manage appointments, forms, and records online. For more information or to schedule an appointment, contact us today. We proudly serve patients from Allen, TX, Anna, TX, Celina, TX, Denton, TX, Forney, TX, Greenville, TX, Lewisville, TX, McKinney, TX, Rockwall, TX, Sherman, TX, Sulphur Springs, TX, and Waxahachie, TX, and surrounding areas. PATIENT PORTAL