“…[33][34][35][36] Functional abnormalities are favored over anatomic abnormalities, because there have been cases of patients who spontaneously improved. [33][34][35][36] Furthermore, YNS has been associated with a number of systemic diseases including rheumatoid arthritis, [42][43][44] Guillain-Barre syndrome, 45 drugs such as bucillamine (a treatment for rheumatoid arthritis), 43,44,46,47 and certain cancers including breast, 39 lung, 48 gallbladder, 49 and lymphoma. 41,50,51 In YNS, nail changes occur in virtually all patients and represent the presenting sign in up to 30% of cases.…”