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Leprosy - Dermatology


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Leprosy: Dermatology
Source: Fitzpatrick's Dermatology 6th eidition

Published in: Health & Medicine
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Leprosy - Dermatology

  2. 2. • Leprosy (Hansen's disease) can be defined as a chronic granulomatous infection and its sequelae, caused by Mycobacterium leprae, and affecting primarily skin and nerves. • 600,000 new cases yearly, worldwide • despite apparently curative antibacterial therapy, one- quarter to one-third of all patients will have a debilitating and permanent neurologic deficit. Father Damien with leprosy patients he ministered to in Hawaii during the 1870s; he was later canonized by the Roman Catholic Church.
  3. 3. EPIDEMIOLOGY • Primarily a disease of developing countries, is endemic in all continents, except Antarctica. • The highest case detection rates are in India, Brazil, Madagascar, Nepal, and Tanzania. • More common in men than in women by a 2:1 ratio • Predominantly a young person's disease, the majority of cases occurring before age 35 years
  4. 4. ETIOLOGY AND PATHOGENESIS • M. leprae, the cause of leprosy, is a noncultivable, gram-positive, obligate intracellular, acid-fast bacillus. • Entry into nerves is mediated by the binding of the species-specific trisaccharide in phenolic glycolipid I to laminin-2 in the basal lamina of Schwann cell-axon units, 11providing a rationale as to why M. leprae is the only bacterium known to invade peripheral nerves.
  5. 5. Granulomatous Spectrum • The most detailed description of the granulomatous spectrum of leprosy came from Ridley and his associates, integrating both clinical and histologic changes. TT (polar tuberculoid), BT (borderline tuberculoid), BB (borderline), BL (borderline lepromatous), LLs (subpolar lepromatous), and, finally, LLp (polar lepromatous)
  6. 6. Peripheral Nerve Changes • Four types of peripheral nerve abnormalities are common in leprosy: (1) nerve enlargement (usually perceived as asymmetry), particularly in those close to the skin, such as the great auricular, ulnar, radial cutaneous, superficial peroneal, sural and posterior tibial; (2) sensory loss in skin lesions;
  7. 7. 3) nerve trunk palsies either with signs and symptoms of inflammation or without such overt manifestations, that is, silent neuropathy, usually with both sensory and motor loss (weakness and/or atrophy) and, if long-standing, also with contracture; (4) acral distal symmetric anesthesia, a withering away, so to speak, of the type C fibers, involving heat and cold discrimination before loss of pain or light touch, beginning in acral areas and, over time, extending centrally but sparing the palms, at least for a while.
  8. 8. The most commonly affected nerves in leprosy. (From Sabin TD, Swift TR, Jacobson RR: Leprosy. In: Dyck PJ, Thomas PK, eds: Peripheral Neuropathy. Philadelphia: Elsevier Saunders. 2005, p 2089, Figure 91-4.)
  9. 9. POLAR TUBERCULOID LEPROSY A solitary, anesthetic, and annular lesion of polar tuberculoid leprosy (TT), which had been present for 3 months. Its sharp margins, erythema, and scale are more evident than its elevation. The central red dots are the sequelae or “footprints” of testing for pinprick perception when it is absent. (If present, the patient withdraws, preventing overtly purpuric consequences.)
  10. 10. One of several lesions of borderline tuberculoid (BT), which had an incompletely annular configuration with satellite papules. Compared to the TT lesion, there is less erythema, no evident scales, but sharp margination, and the footprints of absent pinprick perception are also seen. BORDERLINE TUBERCULOID LEPROSY
  11. 11. BORDERLINE LEPROSY • BB is the immunologic midpoint or mid-zone of the granulomatous spectrum, being its most unstable area, with patients quickly up- or downgrading to a more stable granulomatous posture with or without a clinical reaction. • Characteristic skin changes are annular lesions with sharply marginated interior and exterior margins, large plaques with islands of clinically normal skin within the plaque, giving a “Swiss cheese” appearance, or the classic dimorphic lesion. • Because of instability, the BB posture is short-lived and such patients are evidently rarely seen.
  12. 12. BORDERLINE LEPROMATOUS LEPROSY A characteristic borderline or dimorphic lesion, which is an indurated and elevated annular plaque that has a well defined “tuberculoid” interior margin, but a poorly defined “lepromatous” exterior margin. Having both morphologies, it is termed “dimorphic.”
  13. 13. Multiple lesions in a patient with borderline lepromatous (BL) leprosy. The annular lesions vary in size and are asymmetrically distributed. In contrast, the poorly defined papular and nodular lesions are roughly symmetric. Loss of sensation was present in most lesions.
  14. 14. LEPROMATOUS LEPROSY Multiple skin-colored papular and small nodular lesion in a patient with polar lepromatous (LLp) leprosy. The margination of the lesions is variable, some being poorly defined. The absence of clinical inflammation is evident. Some distortion of the normal helix is arising from diffuse infiltration as well as from the nodular lesions.
  15. 15. Multiple papular lesions, which are solitary and confluent, in a patient with subpolar lepromatous (LLs) leprosy. These multiple, barely palpable, erythematous, and asymptomatic lesions had been erupting over the previous 2 months in a LLs patient. With treatment, as lesions remitted they became mildly hyperpigmented.
  16. 16. With progressive bacillary proliferation, further cellular infiltration, and the consequent thickening of the dermis, the skin is thrown into folds producing the leonine faces often in conjunction with nodular lesions.
  17. 17. Systemic Associations • Because of motor or sensory changes in cranial nerve V, the eye may be at risk in TT and BT disease, as well as in BB, BL, and LL leprosy. • numerous changes in the cornea and anterior chamber are possible, iritis being a common serious change. • Corneal insensitivity is the common, treatable change.
  18. 18. INDETERMINATE LEPROSY • Indeterminate leprosy is a term with nearly as many meanings as it has users: - “designating an early lesion, appearing before the host makes a definitive immunologic commitment to cure or to an overt granulomatous response.” • hypopigmented macule • with or without a sensory deficit • acid-fast bacilli, if found, are in very small numbers • rare in clinic
  19. 19. Indeterminate leprosy, A solitary erythematous macule on the face of a young family member of a patient with lepromatous leprosy.
  20. 20. Variants: PREGNANCY AND POSTPARTUM • Pregnancy is a precipitating factor for leprosy in 10 to 25 percent of women patients. • Of the drugs used to treat leprosy, none have been proven to be safe for the fetus and one is clearly contraindicated. • Fetal damage attributable to dapsone evidently has not been observed, hence continuation of dapsone in multibacillary patients is usually recommended. • The wishes of the patient should be carefully considered. Untreated, lactating BL and LL patients have viable bacilli in their milk, but no definable risk has been identified in infants ingesting such bacilli.
  21. 21. LABORATORY FINDINGS • Most laboratory changes occur in LL or extensive BL disease. • Hyperglobulinemia -> increased sedimentation rate • A biologic false-positive serologic test for syphilis, anemia of chronic disease, and mild lymphopenia are also common • Clinically insignificant antiphospholipid antibodies are present in 50 percent of LL patients, and may give rise to a lupus anticoagulant or agglutination of sheep erythrocytes (Rubino factor). • Elevated serum lysozyme and angiotensin-converting enzyme • Proteinuria, not uncommon, is associated with a focal glomerulonephritis • High serumfollicle-stimulating hormone (FSH) and luteinizing hormone (LH) values, but low testosterone levels
  22. 22. DIAGNOSIS • A firm diagnosis of leprosy requires the satisfaction of one of two criteria: - a consistent peripheral nerve abnormality - the demonstration of mycobacteria in tissues. • Risk factors: -(1) birth or residence in an endemic area, which is almost sine qua non for the diagnosis -(2) a blood relative with the disease, which could reflect transmission, common genetic makeup, or common environmental exposure - (3) armadillo (seven-banded) exposure in North American.
  23. 23. • The possibility of leprosy also should be suggested by particular clinical constellations such - (1) simultaneous skin lesions and peripheral nerve abnormalities - (2) a differential diagnosis that includes granuloma, vasculitis, or lymphoma - (3) a peripheral neuropathy of unknown type in a patient in or from an endemic area, the so called pure neuritic leprosy - (4) simultaneous palsies of cranial nerves V and VII, considered to be leprosy until proven otherwise.
  24. 24. TREATMENT • Medical management is directed at the infection itself, or if present, at a reactional state. - For paucibacillary disease (TTor BT) the World Health Organization (WHO) recommends the combination of unsupervised dapsone (bacteriostatic) 100 mg daily and supervised rifampin (bactericidal) 600 mg monthly for a duration of 6 months. - For multibacillary disease (BB, BL, and LL) the WHO recommends unsupervised dapsone 100 mg daily, supervised rifampin 600 mg monthly and clofazimine 50 mg daily, unsupervised, and 300 mg monthly supervised for a routine duration of 2 years.