Authors who wrote about LV have hypothesized about etiology and pathogenesis based on observations made by them in their own patients. The preceding quotations demonstrate compellingly that there is no universally accepted concept about etiology and pathogenesis of LV. A broad variety of clinical and laboratory findings have been reported to be associated with LV. Some of them seem to be mere coincidence, such as "chronic eczema," [12] atopic dermatitis, [12] allergic rhinitis, [17] contact sensitivity, [13,14] psoriasis, [14] and tinea, [14] cholelithiasis, [12] hypertension, [12] drug allergies, [13,14] diabetes mellitus, [14] myasthenia gravis, [14] irritable bowel syndrome, [17] chronic obstructive pulmonary disease, [17] hyperlipidemia, [17] and gout [17]. The idea that infections could be the cause of LV can be found in early publications, e.g., tuberculosis, [3,12,20] nasopharyngeal infections, [20] and urinary tract infections, [20] but the mechanism of pathogenesis remained obscure.

Another group of diseases that have been observed to be associated often with LV are disorders of coagulation of various causes, such as cryoglobulinemia, [27] protein C deficiency, [29,37] antiphospholipid syndrome, [35,38] anticardiolipin antibodies, [47] factor V Leiden mutation, [40,48] factor XII deficiency, [45] antithrombin III deficiency, [39] heterogenous prothrombin G20210A gene mutation, [49] homocysteinemia, [44,50] inherited thrombophilia, [51] increased activity of platelets, [18,22] raised fibrinopeptide A levels, [17] and decreased thrombomodulin expression on endothelial cells. [34]

Rheumatologic diseases are mentioned with repeatability as occuring together with LV, among them being ankylosing spondylitis, [13] rheumatoid arthritis, [14] mononeuritis multiplex, [13,14] systemic lupus erythematosus, [14] Raynaud`s phenomenon, [14] and panarteritis nodosa. [14] The same is true for various diseases typified by impaired perfusion, such as thrombophlebitis, [14] arteriosclerosis, [14] myocardial infarction, [14] angina pectoris, [17] abdominal aortic pathology, [20] and bilateral iliofemoral stenosis. [27] A last group of diseases that seem to occur together with LV are neoplasms, e.g., gamma heavy chain disease, [28] carcinoma of the cervix, [12] carcinoma of the bladder, [14] carcinoma of nasopharynx, [14,20] and systemic B cell lymphoma. [41]