Tuberculoid Leprosy

Diagnosis: Tuberculoid Leprosy

Annular hypopigmented plaque of tuberculoid leprosy.

Clinical Presentation

Annular hypopigmented plaque of tuberculoid leprosy.

Clinical History

Submitted by Alaa Saad. Originally posted September 14, 2010.

Treatment

See case discussion.

Differential Diagnosis

• Granuloma annulare • Sarcoidosis • Mycosis fungoides • Tinea corporis • Vitiligo (tuberculoid leprosy) • Morphea • Secondary syphilis • Lupus vulgaris (cutaneous TB)

Key Learnings

• Caused by Mycobacterium leprae — obligate intracellular acid-fast bacillus • Clinical spectrum (Ridley-Jopling): tuberculoid (TT) ← borderline → lepromatous (LL) • Tuberculoid: few, well-defined, hypopigmented, anesthetic plaques; paucibacillary • Lepromatous: numerous, poorly-defined papules/nodules; diffuse skin infiltration; multibacillary • Nerve involvement is the hallmark — predilection for cooler body areas (ears, nose, fingers) • Enlarged peripheral nerves on palpation is a key clinical finding • Type 1 reaction (reversal): cell-mediated; edema and inflammation of existing lesions • Type 2 reaction (erythema nodosum leprosum): humoral; tender nodules, fever, systemic symptoms • Still endemic in parts of Brazil, India, Southeast Asia, and Gulf Coast of USA (armadillo exposure)

Tags: tuberculoid, leprosy, alaa saad