Yellow nail syndrome (YNS) is a rare disorder first described in 1927 and diagnosed based on a triad associating yellow nail discoloration, lower limb lymphedema, and respiratory manifestations including bronchiectasis, pleural effusion (usually lymphocyte-rich exudates) and rhinosinusitis with unknown pathogenesis.1 YNS usually occurs in adults over 50 years old and there is no gender preference. F. Maldonado et al. retrospectively analyzed 41 YNS patients and revealed that 26 patients (63%) presented with lymphedema as the main manifestation; all but one patient had chronic respiratory manifestations.2 The classic triad was simultaneously present in 27-60% of patients with the syndrome.3
YNS was most plausible cause of leg edema in this case. When YNS is diagnosed, it is important to exclude other possibilities such as heart failure, hypothyroidism, renal failure, liver cirrhosis, tuberculous pleuritis and other disorders related to yellow nail (onychomycosis, drugs such as D-penicillamine, bucillamine), but in our case, there were no findings that indicated such a differential diagnosis. The long-term outcome for YNS is not well known, but prognosis may be poor and relation to cancer has been shown in small sets of patient groups.2 Since there is no evident specific therapy to date, the prescribed therapy is usually selected based on manifestation of patient symptoms.2 L. Valdes. et al. reported that the most effective treatments for symptomatic pleural effusion appear to be pleurodesis and decortication/pleurectomy, since a total of 81.8% patients showed partial or complete response.4
In our current case, decreased bilateral micronodules were obtained after reintroduction of daily erythromycin. Yellow nail, pleural effusion and leg edema were then stable without any other symptoms.