There is a stark difference between highly specific diagnostic criteria and those with more flexibility around symptom presentation. As a result, there are almost 24,000 possible symptom combinations for panic disorder in the DSM-5, compared with just one possible combination for social phobia (Galatzer-Levy and Bryant, 2013).
Reference: I. R. Galatzer-Levy, and R. A. Bryant (2013). 1636,120 Ways to have posttraumatic stress disorder. Perspect. Psychol. Sci., 8 (2013), pp. 651-662