A Tricky Diagnosis of Poncet’s Disease

Abstract

Erythema nodosum (EN) is a type of panniculitis often benign and self-limited. It may, however, be associated with numerous causes, the most common being infections (namely streptococcal infections), of which tuberculosis (TB) is also one. We report the case of a 43-year-old woman who was referred to our outpatient department with signs of a recurrent EN along with an asymmetrical oligoarthritis of the lower limbs. The investigation excluded all etiological causes of EN, except the interferon gamma release assay (IGRA) which was positive. It was assumed a latent TB infection was the cause of EN. Treatment with isoniazid was started, besides prednisolone and colchicine, with maintained clinical remission. There are just a few cases published about this subject and this intends to emphasize the importance of medical history and of an exhaustive search for a cause, as it may slip away due to the absence of symptoms.

Poncet's disease: An uncommon presentation of a common disease in Sudan

“…Although the presentation is typical for systemic rheumatological diseases, the autoimmune work‐up was negative, while the Gene‐Xpert was positive for TB. Lourenço et al reported a similar presentation 5 . In their case report, the patient experienced asymmetrical oligoarthritis (knees and ankles) in addition to erythema nodosum but these were not supported by the typical immunological markers 5 .…”

“…5 In their case report, the patient experienced asymmetrical oligoarthritis (knees and ankles) in addition to erythema nodosum but these were not supported by the typical immunological markers. 5 This, accompanied by a positive interferon gamma release assay test pointed towards the diagnosis of TB and subsequently Poncet's disease (PD). 5 In an additional study conducted by Garg et al among 18 patients with acute inflammatory ankle arthritis, eight patients were diagnosed with PD based on a positive Mantoux test and CT scan of the chest showing mediastinal and/or paratracheal and/or unilateral hilar lymphadenopathy with central necrosis.…”

“…In their case report, the patient experienced asymmetrical oligoarthritis (knees and ankles) in addition to erythema nodosum but these were not supported by the typical immunological markers 5 . This, accompanied by a positive interferon gamma release assay test pointed towards the diagnosis of TB and subsequently Poncet's disease (PD) 5 …”

“…5 This, accompanied by a positive interferon gamma release assay test pointed towards the diagnosis of TB and subsequently Poncet's disease (PD). 5 In an additional study conducted by Garg et al among 18 patients with acute inflammatory ankle arthritis, eight patients were diagnosed with PD based on a positive Mantoux test and CT scan of the chest showing mediastinal and/or paratracheal and/or unilateral hilar lymphadenopathy with central necrosis. 6 The accuracy of the results are questioned by the lack of microbiological and histopathological confirmation however it showcase the importance of including PD as a differential diagnosis of acute ankle arthritis in TB-endemic regions.…”

“…PD reported an extrapulmonary site only in 48% of cases. 5 While an extended review of the literature from 2007 to 2012 reported the finding of an extrapulmonary infection in cases of PD to be 60%, 3 and exceeding 70% in their own cohort of patients. 3 In this case, the arthritis resolved after 6 weeks of the commencement of antituberculous therapy.…”