We read with interest the case ‘Erythema nodosum: Atypical presentation of a common disease’ by Whig et al. and have the following comments to offer:
The patient described had multiple erythematous, tender, papulonodular skin lesions of 8 - 10 mm size over both legs, more on the shins. The authors have labelled them as erythema nodosum. Histopathology showed multiple epitheloid cell granulomas with Langhans giant cell reaction in subcutaneous tissue without any evidence of caseous necrosis. However, we feel that the skin lesions were actually lesions of cutaneous tuberculosis (TB). How did the authors rule out cutaneous tuberculosis in the patient? The histopathology in cutaneous tuberculosis will be exactly similar, i.e. the presence of characteristic tubercular granulomas with epithelioid cells, Langhans’ giant cells and lymphocytes. On the other hand, erythema nodosum represents an inflammation of the septa in the subcutaneous fat tissue: A septal panniculitis. Histopathology will show a neutrophilic infiltrate around proliferating capillaries resulting in septal thickening in early lesions that may be associated with hemorrhage. Actinic (Miescher's) radial granulomas—small, well-defined nodular aggregates of tiny histiocytes around a central stellate cleft—are a characteristic finding. Erythema nodosum is usually not associated with vasculitis, although small vessel inflammation and hemorrhage can occur rarely. Lupus vulgaris is the most common clinical type of cutaneous TB in adults, and the second most common type seen in children. Clinically it can present in five different patterns: Plaque form, ulcerative and mutilating form, vegetating form, tumor like form and papular and nodular form. It can develop from direct inoculation, haematogenous spread, direct extension from an underlying organ or by lymphatic spread. The common sites of involvement are head and neck followed by arms and legs. The lesion is usually single and starts as a tiny reddish-brown nodule, which later becomes raised and infiltrated.
We feel that the patient described in the case had cutaneous tuberculosis and responded to antituberculous therapy.
1. Whig J, Mahajan V, Kashyap A, Gupta S. Erythema nodosum: Atypical presentation of common disease Lung India. 2010;27:181–2
2. Singal A, Sonthalia S. Cutaneous tuberculosis in children: The Indian perspective Indian J Dermatol Venereol Leprol. 2010;76:494–503
3. Schwartz RA, Nervi SJ. Erythema nodosum: A sign of systemic disease Am Fam Physician. 2007;75:695–700
4. Hassan I, Ahmad M, Masood Q. Lupus vulgaris: An atypical presentation Indian J Dermatol Venereol Leprol. 2010;76:180–1