{'fraction_non_alphanumeric': 0.03360421699978036, 'fraction_numerical': 0.004612343509773776, 'mean_word_length': 5.31622746185853, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
An unusual cause of bilateral lower limb pitting oedema: Crohn's septal panniculitis diagnostic of erythema nodosum

We present a 25-year-old female, who was admitted to a tertiary referral hospital with painful bilateral pitting oedema of her lower limbs, restricted mobilization and fevers for several weeks. Apart from a history of Crohn’s disease, she had no other significant known co-morbidities. On presentation to the emergency department, she had no gastrointestinal symptoms. One year previously, she had a right hemicolectomy for terminal ileal disease and her Crohn’s disease had since been well controlled with mesalazine, mercaptopurine and adalimumab. Extensive investigations were undertaken to identify a diagnosis, with a wide range of differential diagnoses including cardiogenic causes, hypoalbuminaemia, lymphoedema, vascular insufficiency, sepsis, cellulitis, drug reaction, hepato-renal abnormalities, autoimmune diseases and deep venous thrombosis (DVT). A Doppler ultrasound was performed confirming no evidence of DVT. Chest X-ray showed no evidence of pulmonary oedema and X-rays of the ankles and feet showed no abnormalities. There was no evidence of protein-losing enteropathy, with normal albumin levels (37 g/L). Antinuclear antibodies, human leukocyte antigen B27, rheumatoid factor, myeloperoxidase antibodies, proteinase 3 antibodies and double stranded deoxyribonucleic acid immunoglobulin G were not detected. Cardiac investigations were within normal limits. No specific cause for the bilateral lowel limb pitting oedema was identified. However, on day 5 of admission, after a battery of negative tests, a nuclear bone scan showed inflammatory arthritis involving both ankles and plantar fasciitis (Fig. 1a). This prompted a biopsy of the dorsum of the foot (Fig. 1b) which confirmed septal panniculitis with granuloma, diagnostic of erythema nodosum associated with Crohn’s disease (Fig. 1c). Interestingly, there was no clinical evidence of erythema nodosum at the biopsy site or on the pre-tibial region of leg, but a nodule had developed on the plantar aspect of her foot (Fig. 1d) during her admission. This is not typical of erythema nodosum, as this extra-intestinal manifestation is usually a tender, red nodule on the extensor aspect of lower limbs. It is not usually (as in this case) on the plantar aspect of the foot. Bilateral pitting oedema of the lower limbs is rarely associated with Crohn’s disease. In this case, the bilateral pitting oedema was not suspected to be associated with Crohn’s disease until much later to the admission. There have been few case reports of Crohn’s associated lower limb oedema. One case report of painful leg swelling associated with Crohn’s disease was diagnosed as pyoderma gangrenosum. In another case report, a 21-year-old male with a 4year history of Crohn’s disease had pitting oedema associated with a protein-losing enteropathy, which improved after resection of strictured jejunum. On the other hand, erythema nodosum is a common form of septal panniculitis, which affects up to 15% of Crohn’s patients. It is different from erythema induratum, so-called metastatic Crohn’s disease, which usually manifests on the calves. Erythema nodosum is not specific to inflammatory bowel disease, and may be seen as an immunological response in tuberculosis, sarcoidosis, lymphoma and auto-immune diseases. The management of septal panniculitis including erythema nodosum is usually symptomatic. Non-steroidal anti-inflammatory medications, aspirin, indomethacin, naproxen and potassium iodide and bed rest may be useful. Steroids are not usually required, but may be used for severe disease (1 mg/kg) after underlying infection, sepsis and malignancy have been excluded. Skin manifestations of inflammatory bowel disease may improve with bowel resection, but response has been shown to be unpredictable. Colchicine has been shown to be useful in treatment of erythema nodosum lesions in Behcet’s syndrome, and antitubercular medications for Fig. 1. Examination and investigation findings. (a) Bone scan demonstrating diffuse hyperaemia in the feet consistent with soft tissue inflammation. (b) Pitting oedema of left foot and ankle with biopsy site on dorsal aspect (arrow). (c) Histology of skin biopsy of dorsum of left foot, showing a small granuloma (arrow) with central clefting and surrounding lymphohistiocytes, consistent with erythema nodosum (magnification 2.5×; haematoxylin and eosin). (d) Erythema nodusum nodule on the plantar aspect of left foot (arrow).