Texas Dermatology Associates Patient Forms. At Texas Dermatology Associates, we are here to serve you. ... Patient Portal Login. LOG INTO OUR SECURE PATIENT PORTAL. ... Dallas 3900 Junius St., Suite 145 Dallas, TX 75246 Phone: 972-386-7546 Fax: 972-661-3255. Mansfield 1830 E. Broad St., Suite 102.