28-year-old married female presented with a history of swelling and pigmentation/black spots in both lower limbs, intermittent fever, and polyarthritis

Discussion of case

The 28-year-old female was treated symptomatically for fever without any localizing sign, and the subsequent evaluation indicated that she was pregnant for 6 weeks. Two days after the fever subsided, the development of multiple painful nodular rashes over the lower limb and shin was observed. The fever relapsed in one week with increased swelling and pain over the lower limb and ankle. The presence of a cough was suggestive of lower respiratory tract involvement. She continued to have pain in small and large joints and worsening swelling of the lower limb with erythema was noted. She was subjected to medical termination of pregnancy for fetal growth failure. Doppler conducted for venous thrombosis was negative. Her history revealed that she was previously diagnosed with rheumatic fever and was on penidure prophylaxis.

The probable diagnoses could be erythema nodosum, erythema multiforme, Sweet's syndrome, mycosis fungoides, and blastomycosis. The chances of having the last two diagnoses are unlikely since the patient is young and the history revealed a previous episode of infection. The clinical features noticed during the evaluation indicate that the lesion could be similar to erythema nodosum (EN).

The fever, which occurred one and half months before the clinical presentations, could have triggered EN, thereby suggesting the possibility of an underlying infection and the sequela. The development of autoimmune diseases like connective tissue disease (CTD) and sarcoidosis can be considered for differential diagnosis. Pregnancy has been described to be associated with the development of EN. In addition, spontaneous pregnancy loss can be due to the occurrence of infection, autoimmune disease, or anti-phospholipid antibody (APLA) syndrome.

Table 1: The most common causes of EN

Other rare causes of EN are Chlamydophila pneumoniae and Yersinia infections.^{[1, 2, 3]} Pancreatic panniculitis is a rare complication of pancreatic disease.^[4] Drugs like nonsteroidal anti-inflammatory drugs, antibiotics, and leukotriene-modifying agents can also be rare causes for EN.^[5] Since the patient had an infection-like episode as well as pregnancy failure and no specific drugs were prescribed, the development of EN could be due to the underlying infection (table 1).

Clinical investigations revealed that she had 8.5 gm of Hb% and normal inflammatory parameters. Her chest X-ray was normal, and no connective tissue disease was reported. The result of the APLA work-up was negative. The clinical investigation suggests that there is no possibility of having CTD, sarcoidosis, or tuberculosis. Since the inflammatory parameters were normal, the possibility of systemic disease is less likely, but cannot be excluded.^[6]

The need for histopathology and biopsy always depends on the physician's discretion. A histopathological investigation will help in confirming the diagnosis in patients presenting with tender cutaneous nodules of the legs.^[7] If the clinical examination suggests possible panniculitis, the histologic investigation may not be beneficial. Histopathologically, subcutaneous fat responds to a variety of insults in a limited form with subtle pathologic differences among the conditions. Although biopsy plays a critical role in the diagnosis of panniculitis, it may not be helpful in the differential diagnosis.^[8] In this case, the biopsy was deferred since the occurrence of the disease was presumed to be secondary to infection.

The patient was treated with NSAID, and the follow-up conducted after 3 weeks showed a significant reduction in the signs and symptoms.

Final Diagnosis

The diagnosis can be concluded as post-infective EN.

References

1. Blake, T., M. Manahan, and K. Rodins, Erythema nodosum - a review of an uncommon panniculitis.Dermatol Online J, 2014. 20(4): p. 22376.
2. Choroszy-Krol, I., et al., Infections caused by Chlamydophila pneumoniae.Adv Clin Exp Med, 2014. 23(1): p. 123-6.
3. Rosner, B.M., et al., Clinical aspects and self-reported symptoms of sequelae of Yersinia enterocolitica infections in a population-based study, Germany 2009-2010.BMC Infect Dis, 2013. 13: p. 236.
4. Laureano, A., et al., Pancreatic panniculitis - a cutaneous manifestation of acute pancreatitis.J Dermatol Case Rep, 2014. 8(1): p. 35-7.
5. Borroni, G., et al., Drug-induced panniculitides.G Ital Dermatol Venereol, 2014. 149(2): p. 263-70.
6. Gupta, M., et al., Recurrent erythema nodosum: a red flag sign of hidden systemic vasculitis.BMJ Case Rep, 2013. 2013.
7. Eimpunth, S., et al., Tender cutaneous nodules of the legs: diagnosis and clinical clues to diagnosis.Int J Dermatol, 2013. 52(5): p. 560-6.
8. Tomasini, C., F. Lentini, and G. Borroni, The role of skin biopsy in the diagnosis of panniculitides.G Ital Dermatol Venereol, 2013. 148(4): p. 335-49.