Hansen’s Disease (Leprosy)
A chronic infectious disease caused by Mycobacterium leprae (or M. lepromatosis), primarily affecting the skin, peripheral nerves, and upper respiratory mucosa.
Immunological Spectrum
| Form | Immune Response | Clinical Features |
|---|---|---|
| Tuberculoid (TT) | Strong Th1 (Cell-mediated) | Few, well-defined, hypopigmented, anesthetic plaques. |
| Lepromatous (LL) | Weak Th1 (Humoral only) | Diffuse infiltration, “leonine facies,” loss of eyebrows, high bacterial load. |
Management Pillars
- Diagnosis: Skin biopsy (acid-fast bacilli) and slit-skin smears.
- Treatment: Multidrug Therapy (MDT) including Rifampin, Dapsone, and Clofazimine.
- Reaction States: Watch for Type 1 (Reversal) and Type 2 (ENL – Erythema Nodosum Leprosum) reactions, which require urgent management with corticosteroids or Thalidomide.
High-Yield Exam Pearl:
- Anesthesia: Leprosy is the #1 cause of peripheral neuropathy worldwide. Always check for loss of sensation in skin lesions.
- Leonine Facies: Classic sign of advanced Lepromatous Leprosy (LL) due to massive infiltration of the skin by bacilli.