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  1. 1. ASHAR IQBAL LODI 080201134
  2. 2. Introduction Lepra reactions comprise several common immunologically inflammatory states that can cause considerable morbidity. Some of these reactions precede diagnosis and institution of effective antimicrobial therapy. Other reactions occur after the initiation of appropriate chemotherapy.
  3. 3. Types Lepra Reaction are of two types : 1. Type 1 Lepra Reactions : (Downgrading and Reversal Reactions) 2. Type 2 Lepra Reactions : Erythema Nodosum Leprosum (ENL)
  4. 4. Type 1 Lepra Reactions : It is delayed type of hypersensitivity. Occur in patients with borderline forms of leprosy . Classic signs of inflammation within previously involved macules,papules and plaques,which are markedly erythematous, swollen and oedematous. Mainly involves the trunk. Occasionally,there is appearance of new skin lesions,neuritis and fever (low-grade). Associated with large numbers of T cells bearing receptors – a unique feature of leprosy.
  5. 5. Contd.. Cutaneous lesions ,which are markedly erythematous, swollen and oedematous with sharp margins are common. Desquamation and ulceration of lesions may occur. Nerve trunk involvement is also common . Ulnar nerve involvement at the elbow (most common), painful and exquisitely tender, results in clawing of hand. Wrist drop due to radial nerve involvement. Footdrop occurs when peroneal nerve is involved. Facial palsy may also be associated . Edema is the most characteristic microscopic feature.
  6. 6. Cutaneous Lesions inType 1 Lepra Reaction
  7. 7. Facial Palsy and claw hand in Type 1 Lepra ReactionA)Claw Hand with ulceration of palmar surface.A)Loss of longitudinal arch with flat/boat shaped foot
  8. 8. Histology of Type 1 Lepra Reaction
  9. 9. Contd.. Downgrading Reactions :  When type 1 lepra reactions precede the initiation of appropriate antimicrobial therapy.  Histologically , more lepromatous .  Loss of focalization and tubercle formation.  Decrease in number of lymphocytes.  Epithelioid cells co-differentiate towards simple histiocytes and may show intracellular oedema.  Bacillary multiplication & rising morphological index.  Extracellular oedema.
  10. 10. Contd. Reversal Reactions :  Occur after the initiation of antimicrobial therapy.  Histologically,more tuberculoid.  Oedema and increase in lymphocytic infiltration & volume.  Macrophage differentiation towardsepitheloid cells and giant cells take appearance of Langhan’s cells.  Occasionally,necrosis with in the granuloma.  Increased number of bacilli & morphological index falls.  Occur in the first months or years after the initiation of therapy.  Typified by TH 1 cytokine profile,with an influx of CD4+ T helper cells and increased levels of IFN- and IL-2.
  11. 11. Type 2 Lepra Reactions : Erythema nodosum leprosum (ENL) occurs exclusively in patients near the lepromatous end of the leprosy spectrum (BL-LL) and is more severe. It is Type III hypresensitivity reaction. 30 % of all lepromatous cases have at least one attack of ENL. 90 % of cases follow the institution of chemotherapy, generally within 2 years . May precede diagnosis and initiation of therapy . Dome-shaped lesions with ill-defined margins .
  12. 12. Contd. Associated with elevated levels of circulating tumor necrosis factor (TNF),TH2 cytokine profile and high levels of IL-6 and IL-8. Hence,thought to be a cause of immune complex deposition due to the antigen from the dying bacilli. Histologically,  Focus of inflammation is away from the major skin lesions,deep in the dermis.  Polymorph infiltration,oedema & cellular disintegration.  Few bacilli at centre of reaction site (More if severe).  Vascular necrosis with haemorrhage and ulceration.
  13. 13. Contd. Most common features are :  Crops of painful,swollen,tender,erythematous, shiny papules (resolve in a few days to a week but may recur), sitting on the skin or involving deep dermis mainly on the face and extremities with fever.  Malaise  Symptoms of neuritis ,uveitis, orchitis , lymphadenitis , glomerulonephritis .  Anemia .  Leukocytosis .  Abnormal liver function tests (increased aminotransferase levels).  Arthiritis and Iridocyclitis.
  14. 14. Cutaneous Lesions inErythema nodosum leprosum
  15. 15. A) Unusual presentation in ENL B) Histology of ENL
  16. 16. Contd. Patients may have a single bout of ENL or chronic recurrent manifestations. Bouts may be mild or severe and generalized & may rarely cause death. Skin biopsy reveals vasculitis or panniculitis characteristically with polymorphonuclear leukocytes and sometimes with lymphocytes. Presence of HLA-DR framework antigen of epidermal cells (marker of delayed hypersensitivity). Higher levels of IL-2 and IFN- is usually seen in polar lepromatous disease.
  17. 17. Lucio’s Phenomenon : Unusual reaction seen exclusively in patients from the Caribbean and Mexico having diffuse lepromatous form of lepromatous leprosy,who are left untreated. Patient develops recurrent crops of large,sharply marginated,ulcerative lesions (lower extremities). May be generalized and fatal as a result of secondary infection and consequent septic bacteremia.
  18. 18. Contd. Histologically,  Ischemic necrosis of the epidermis and superficial dermis.  Heavy parasitism of endothelial cells with AFB.  Endothelial proliferation and thrombus formation in large vessels of the deeper dermis. Probably,mediated by immune complexes (like ENL).
  19. 19. b) Histology ofa) Lesions on buttocks and thighs Lucio’s Phenomenon in Lucio’s Phenomenon