Table 1.

Comparison of classifications of leprosy proposed by World Health Organization and Ridley–Jopling.

Classification		Brief description
WHO (1987)	Ridley–Jopling [21]	Number of skin lesions	Neurological damage	Bacteriology: microscopic criteria
Paucibacillary
1 skin lesion	Tuberculoid (TT)	Unique and infiltrated lesions	No neurological damage	Negative
2–5 skin lesions	Borderline tuberculoid (BT)	Stasis and hypopigmented lesions few or many lesions of varying size	Little neurological damage little or no neurological damage	Negative negative/1+
Multibacillary
>5 lesions	Borderline borderline (BB)	Multiple lesions and maculopapular	Late thickening of the nerve	≧2+
	Borderline lepromatous (BL)	Multiple lesions, maculopapular, and nodules	Late thickening of the nerve	≧2+
	Lepromatous (LL)	Multiple lesions, maculopapular, and nodules	Late thickening of the nerve	≧2+

Note. 1+ or 2+: microscopic criteria when acid-fast bacilli were observed using Ziehl–Neelsen stain; negative, no acid-fast bacilli observed; BL, borderline lepromatous; BT, borderline tuberculoid; IND, indeterminate; LL, lepromatous leprosy; TT, tuberculoid leprosy.