A 43-year-old male presented with asymptomatic cutaneous lesions chiefly involving the face, trunk, forearms and legs for the past six months. As the older lesions gradually enlarged, new lesions appeared. Examination revealed multiple asymmetrically distributed, annular, erythematous, indurated plaques with sharply punched out inner margins with normal skin in the centre and sloping outer margins. Irregular lesions were also seen. The right greater auricular and bilateral ulnar nerves were thickened and non-tender. Altered tactile sensations were demonstrable over the lesions on the extremities, but no motor loss was observed. Skin smears from the ear lobe and from an indurated plaque was positive for M.leprae. Based on the characteristic morphology of the lesions and other clinical findings, a diagnosis of mid-borderline or borderline-borderline (BB) leprosy was made. It appeared to be a case downgrading borderline leprosy and the patient was treated with standard MB MDT, to which he responded well.
BB leprosy is the immunologic midpoint in the fascinating clinical spectrum of the granulomatous disease. It is the most unstable and uncommon form.[1] These patients upgrade or downgrade to a more stable clinical form at the earliest. Cutaneous lesions are characteristically annular plaques with sharp interior and exterior borders [Figures 1 and 2].[2] Large plaques with islands of clinically normal skin within the plaques give rise to a “Swiss cheese” appearance.[2] Lesions are numerous but are asymmetrical. Determining the type of leprosy is not based on clinical features alone. It involves the histological, bacteriological and immunological facets too, and these objectives seemed to have been met with in Ridley-Jopling classification.[3] Consistency among clinical, histological, bacteriological and immunological parameters is perhaps less than 50%.[3] Hence, identifying characteristic cutaneous lesions is useful for the classification of leprosy.
Figure 1.
Annular plaque with sharp inner margin and sloping outer margins
Figure 2.
Annular and irregular plaques with normal skin in the centre
Footnotes
Source of Support: Nil
Conflict of Interest: None declared
REFERENCES
- 1.Sharma VK. Classification and clinical features. In: Valia RR, editor. Textbook and Atlas of Dermatology. Vol. 2. Mumbai: Bhalani publishing house; 2001. pp. 1578–603. [Google Scholar]
- 2.Rea TH, Modlin RL. Leprosy. Fitzpatrick's Dermatology in General Medicine. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, editors. Vol. 1. Philadelphia: McGraw-Hill; 2008. pp. 1786–96. [Google Scholar]
- 3.Majumdar S, Srivastava G, Kumar P. Clinicohistological disparity in leprosy. Indian J Dermatol Venereol Leprol. 2003;69:178–9. [PubMed] [Google Scholar]