Lupus vulgaris, a form of cutaneous TB, presents as a reddish-brown plaque with an "apple-jelly" appearance on diascopy, a specific sign not seen in leprosy.
Cutaneous leishmaniasis typically forms a "volcano-like" ulcer with a heaped-up border, a different morphology than the anesthetic patches or nodules of leprosy.
The papules of lichen planus are characteristically violaceous, polygonal, and intensely itchy, whereas leprosy lesions are typically hypoesthetic (numb).
The plaques of CTCL are often pruritic, whereas leprosy plaques are defined by their loss of sensation.
This is a common condition of mild, hypopigmented, slightly scaly patches on the face of children, which is not anesthetic.
This superficial fungal infection presents with scaly patches that are positive on a KOH prep, and sensation is normal.
Psoriatic plaques are characterized by a thick, silvery scale and normal sensation.
The reddish-brown plaques of sarcoidosis can mimic leprosy, but they are not anesthetic and are confirmed by a biopsy showing non-caseating granulomas without acid-fast bacilli.
The lesions of secondary syphilis are protean but are not associated with a loss of sensation.
This fungal infection presents as an annular, scaly plaque with an active border and normal sensation, and is confirmed by a KOH test.
