Leprosy in Child
Alerts and Notices
Synopsis

Leprosy spreads via human-to-human transmission. Armadillos are also a reservoir, and direct contact with armadillos is thought to be a risk factor for development of leprosy. The average incubation period for M leprae is about 5 years, with a range from 2 to over 30 years.
Mycobacterium leprae has a predilection for the cooler parts of the body, skin, peripheral nerves, upper respiratory system, anterior eye chambers, and testes.
Leprosy is classified into 5 disease types based on clinical, immunologic, and pathologic criteria:
- Tuberculoid leprosy (TT)
- Borderline tuberculoid leprosy (BT)
- Midborderline leprosy (BB)
- Borderline lepromatous leprosy (BL)
- Lepromatous leprosy (LL)
Peripheral neuropathy may occur across the spectrum before, during, and after treatment. Small nerve fibers conveying fine touch, temperature, and pain sensations are the most impaired. During immune exacerbations (reactions), fever, arthralgias, neuritic pain, uveitis, and orchitis may occur.
Type 1 lepra reaction and erythema nodosum leprosum (type 2 lepra reaction) are 2 types of reactive states seen during alteration of the patient's immune response. They can occur before, during, or after therapy. Lucio phenomenon is a rare reaction seen in patients with multibacillary leprosy due to endothelial invasion of M leprae.
Mycobacterium lepromatosis is a newly identified mycobacterium that usually causes diffuse LL or LL. Cases of BL leprosy have also been reported, as have those with Lucio phenomenon and erythema nodosum leprosum.
Codes
ICD10CM:A30.9 – Leprosy, unspecified
SNOMEDCT:
81004002 – Leprosy
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
Hypopigmented patches:Erythematous macules:
- Psoriasis
- Seborrheic dermatitis
- Tinea corporis
- Nummular dermatitis (nummular eczema)
- Syphilis
- Mycosis fungoides
- Psoriasis
- Leishmaniasis (Old World and New World)
- Seborrheic dermatitis
- Tinea corporis
- Granuloma annulare
- Nummular dermatitis (nummular eczema)
- Lichen planus
- Sarcoidosis
- Keloids
- Dermatofibromas
- Blastomycosis
- Tuberculosis
- Leishmaniasis (Old World and New World)
- Yaws
- Syphilis
- Lymphoma
- Metastases
- Erythema nodosum
Histoid leprosy clinically simulates:
- Xanthoma
- Neurofibroma
- Dermatofibromas
- Reticulohistiocytosis
- Sarcoidosis
- Keloids
- Molluscum contagiosum
- Mycobacterial spindle cell pseudotumor
- Papulonodular variant of secondary syphilis sparing the palms and soles
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Management Pearls
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Therapy
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References
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Last Reviewed:07/04/2022
Last Updated:07/05/2022
Last Updated:07/05/2022