Erythema Nodosum (EN) is the inflammatory condition of the subcutaneous fat and considered the most common panniculitis. The process usually shows an acute onset and self-limited course. It is classically characterized by the sudden eruption of several erythematous, tender, non-ulcerating nodules and plaques, typically located on the shins, ankles and knees. Occasionally, other areas may be involved, including the thighs, extensor aspects of the arms, neck and even the face. The nodules range from 1 to 5 cm or more in diameter and may become confluent resulting in erythematous plaques. Early lesions show a bright red colour and are raised slightly above the skin. After a few days, they become flat, with a livid red or purplish colour. Finally, they show a yellow or greenish appearance, often taking on the look of a deep bruise, and for that reason the process was classically named ‘erythema contusiformis’ The condition normally resolves spontaneously without ulceration, scarring or atrophy, but recurrent episodes are common. Often, acute bouts of EN are associated with a fever of 38–39°C, fatigue, malaise, arthralgia, headache, abdominal pain, vomiting, cough or diarrhoea [1]. EN is a cutaneous reactive process that may be triggered by a wide variety of infectious and inflammatory disorders and, less commonly, by malignant neoplasms and medications. The most common triggers are Bacterial and Viral infections, Sarcoidosis and Inflammatory bowel disease, often the aetiology remains unidentified. Women seem to be less affected than men, with a ratio of 6:1, and the disease occurs mostly between the second and fourth decades of life even though all ages may be concerned [2].
Case Presentation
A 33-year-old man presented with 5 days of fever, cough, coryza and severe fatigue. One day ago, he noticed, eruption of painful tender violaceous lesions on both shins, for which he took consultation. The patient was working in a private firm and had no known comorbidity, medication history or allergy. The physical examination only revealed tender and warm cutaneous lesions on both shins.
Investigations
The laboratory findings showed elevated serum C reactive protein, serum ferritin, abnormal liver function tests, lymphopenia, and anaemia. An elevated erythrocytes sedimentation rate was observed. Considering the COVID-19 pandemic and the suggestive symptoms and blood investigations, a nasopharyngeal swab was performed, and transcription (RT)-PCR came out to be positive for COVID 19. An extensive infectious panel that included a viral hepatitis workup and HIV screening was negative. Patient already had chest CT done from private diagnostic centre which showed several micronodular and centronodular lesions located predominantly at the superior and medial pulmonary lobes, which were interpreted as ground-glass opacifications. Sarcoidosis and tuberculosis were excluded by chest X-ray and negative tuberculin test. Owing to a high clinical index of suspicion and the patient’s reluctance to undergo a procedure, skin biopsy and other blood investigations were not performed.
Treatment
Patient was advised home isolation and symptomatic treatment for COVID 19 infection was started. Paracetamol for analgesia and ointment betamethasone for local applications was also added. NSAIDS and systemic steroids were avoided in context of COVID 19 infection. Patient was further advised bed rest and limited physical activity.
Outcome and Follow-Up
Within 1.5 weeks, the nodules got flattened with complete resolution of dermatological lesion in another 2 weeks.
Viral infections such as infectious mononucleosis, hepatitis B and C, HIV, herpes simplex virus and Epstein-Barr virus etc., commonly identified aetiological factor of EN, have been extensively described in the literature. Other common aetiologies include Streptococcal infections and paravaccinia virus [3]. COVID 19 pandemic being recent in origin, much literature is not available on various associated dermatological symptoms. Recalcati et al., have described cutaneous manifestations included erythematous rash, widespread urticaria and chickenpox-like vesicles, in 20.4% of patients among their cohort of 88 patients [4]. Progressing pruritic lesions on both heels that became erythematous plaques were also reported in a 28-year-old healthy woman infected with COVID 19 [5]. In another study Manalo et al., reported two cases of transient unilateral livedo reticularis, as a manifestation of COVID-19 which is thought to be due to a micro embolic event.
In the present case there was typical presentation of tender erythematous plaques on both the shins with nodular aspect on palpation along with characteristics features of COVID 19 infection as confirmed RT-PCR. Frequent aetiologies were ruled out by various testing modalities but no commonly known trigger was found. The patient was managed symptomatically, and advised rest and leg raising, which lead to a slow but complete recovery.
According to some investigators, EN results from immune complex deposition in and around veins of the connective tissue septa of the subcutis, while others purpose type IV delayed hypersensitivity reaction as a possible pathogenetic mechanism [1].
EN frequently remained self-limiting dermatological condition with unidentified and untreated exact aetiology. Most commonly treatment include rest and non-steroidal anti-inflammatory drugs like Indomethacin, along with treatment of the etiological factor. Systemic glucocorticoids, dapsone, colchicine or hydroxychloroquine may be used as alternative agents [1]. Albeit infrequently documented, COVID-19 infection has emerged as a potential aetiology for EN.
Griffiths CE et al. "Rook's textbook of dermatology, 4 volume set." John Wiley & Sons, 2016.
Requena L, Yus ES. "Erythema nodosum." Dermatologic Clinics, vol. 26, no. 4, 2008, pp. 425–438.
Cribier B. et al. "Erythema nodosum and associated diseases: a study of 129 cases." International Journal of Dermatology, vol. 37, no. 9, 1998, pp. 667–672.
Recalcati S. "Cutaneous manifestations in COVID-19: a first perspective." Journal of the European Academy of Dermatology and Venereology, vol. 34, no. 5, 2020.
Estébanez A. et al. "Cutaneous manifestations in COVID-19: a new contribution." Journal of the European Academy of Dermatology and Venereology, 2020.
Download PDF
Download PDF
Download PDF
Download PDF
Download XML
