Non-ulcerative Variant of Erythema Induratum of Bazin in an Indian Female.

Sir,

Erythema induratum of Bazin (EIB) is a chronic recurrent disease characterized by erythematous plaques and subcutaneous nodules, which usually ulcerate, affecting the lower legs of adult women.[1] EIB is a rare entity among cutaneous tuberculosis and in an Indian study, EIB accounted for 1.5% of the total cases of cutaneous tuberculosis.[2]

We present a case of a middle-aged female with atypical features, including annular plaques and non-ulcerative nodules, diagnosed as EIB.

A 58-year-old hypertensive and diabetic female presented with a 10-month history of a single, erythematous, and depressed plaque over the right lower leg. There was history of multiple, painful, red raised lesions over the anterior aspect of the right leg since 3 weeks. There was no history of trauma, radiation exposure, vaccination, loss of weight, fever, cough, and family or personal history of tuberculosis. On examination, there was a 3 cm × 4 cm ill-defined, erythematous, indurated, tender plaque on the anteromedial aspect of the right lower leg [Figure 1]. Multiple well-defined erythematous annular plaques were present over the anterior aspect of the right leg [Figure 1]. Two violaceous, tender 1 cm × 1 cm nodules were present on right calf. There was no ulceration or pus discharge. Systemic examination did not reveal any abnormality. BCG scar was noted on left upper arm.

Figure 1

One single indurated plaque (blue arrow) and multiple erythematous annular plaques (black arrows) on anteromedial aspect of right leg. Inset on right side showing follow-up image after 1 week (resolution of annular plaques)

A clinical differential diagnosis of deep morphea, necrobiosis lipoidica, and erythema induratum was considered. Blood investigations revealed mild anemia, elevated ESR (51 mm/h), and elevated CRP (14 mg/L). Mantoux test was positive (30 mm × 30 mm). Chest X-ray was normal. CT chest revealed few small parenchymal nodules in the right upper lobe. Tissue biopsy from the indurated [Figure 2] and annular plaque [Figure 3] were suggestive of erythema induratum. CBNAAT from the tissue could not detect M. tuberculosis.

Figure 2

Histopathology of indurated plaque showing septal panniculitis (black arrow) and giant cell-rich granuloma with lobular panniculitis (blue arrow) (stain H and E, 40×). Inset on right side showing marked area of vasculitis (blue arrow) (H and E, 400×)

Figure 3

Histopathology of annular plaque showing lobular panniculitis (H and E, 100×)

Based on the above findings, the patient was started on standard anti-tubercular therapy (ATT). Within 1 week of initiation of ATT, significant improvement was noted. The erythema decreased over the indurated plaque and the new erythematous annular lesions started to resolve [Figure 1]. Patient was followed up for 1 month with persistent improvement after which she lost to follow up.

The morphological presentation was interesting in this case, with the presence of annular plaques and non-ulcerating nodules, which were present on the anteromedial aspect of the right lower leg and calf, respectively. There are very few cases of EIB presenting as annular plaques.[3] Nodules generally ulcerate in EIB, but in this case, the nodules did not ulcerate. EIB lesions appear mostly as a granulomatous lobular panniculitis on histopathology.[4] However, in this case, the histopathology showed septal and focal lobular panniculitis. Early response to ATT was seen in this case within 1 week of initiating ATT, whereas most studies showed response in 3–4 weeks after starting ATT.[15]

Conclusion

This case is being presented to emphasize that there can be unusual presentations of EIB and its early suspicion can help to find the underlying foci of tuberculosis. Therefore, it is of paramount importance to conduct a detailed search for the foci of tuberculosis in highly endemic countries such as India.

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Conflicts of interest

There are no conflicts of interest.