Leprosy classification
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
The Ridley Jopling classification and the WHO classification are the two most widely used systems to classify Leprosy. These classification systems are based on clinical, microbiologic and histopathological features, and are used to determine the patient's prognosis and the treatment regimen.[1][2][3]
Classification
Leprosy may present with a variety of clinical, histopathological and bacterial manifestations. Different classes of Leprosy type determine prognosis, infectivity rate and the appropriate treatment.[1]
There are different systems for classifying leprosy. However, the two more common include the WHO and the Ridley-Jopling.
| WHO | Ridley-Jopling | ICD-10 | MeSH | Description | Lepromin test | Immune target |
|---|---|---|---|---|---|---|
| Paucibacillary | tuberculoid ("TT"), borderline tuberculoid ("BT") | A30.1, A30.2 | Tuberculoid | It is characterized by one or more hypopigmented skin macules and anaesthetic patches, where skin sensations are lost because of damaged peripheral nerves that have been attacked by the human host's immune cells. | Positive | bacillus (Th1) |
| Multibacillary | midborderline or borderline ("BB") | A30.3 | Borderline | Borderline leprosy is of intermediate severity and is the most common form. Skin lesions resemble tuberculoid leprosy but are more numerous and irregular; large patches may affect a whole limb, and peripheral nerve involvement with weakness and loss of sensation is common. This type is unstable and may become more like lepromatous leprosy or may undergo a reversal reaction, becoming more like the tuberculoid form. | ||
| Multibacillary | borderline lepromatous ("BL"), and lepromatous ("LL") | A30.4, A30.5 | Lepromatous | It is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis (nose bleeds), but, typically, detectable nerve damage is late. | Negative | plasmid inside bacillus (Th2) |
Ridley Jopling Classification
There are 6 classes in the Ridley Jopling classification scheme. This classification is based on the following:[4]
- Cutaneous elements
- Neurological elements
- Biopsy findings
- Immunological status
- Presence of acid-fast bacilli in dermis
Tuberculoid or Pauci-bacillary Pole
This is the least severe form of the disease. In this form of the disease the following are present:
- 1 to 3 well-defined lesions with central hypopigmented area and hypoesthesia
- Well-developed immune response
- Granulomatous inflammation
- Rare acid-fast bacilli
Lepromatous or Multi-Bacillary Pole
In this form of the disease the following are present:
- Multiple undefined nodular lesions throughout the body
- Weak immune response
- Evidence of foamy macrophages in dermis filled with mycobacteria
- Patients are immunocompetent, despite not being able to fight mycobacterium leprae
Intermediate, Dimorphous or Borderline State
This last category is divided into 3 subcategories:
Borderline Tuberculoid, or BT
- Progression towards the tuberculoid pole
- Increasing cell-mediated immunity
- Inflammation of the nerves and skin
Mid-Borderline, Borderline-Borderline, or BB
This is considered to be where the disease usually begins, progressing towards one of the poles afterwards.[1]
Borderline Lepromatous, or BL
- Progression towards the lepromatous pole
- Common before treatment initiation
- Loss of cell-mediated immunity
Indeterminate
- Early unspecific lesions
- Nerve infiltrates, lacking required criteria for being classified as above mentioned.
- Used only when there is diagnostic proof of leprosy, from a biopsy sample, with evidence of mycobacteria leprae and perineural infiltrates but the disease is not advanced enough to show the clear patient position in the leprosy classification.
WHO classification
The WHO organization has defined a more simple and straightforward classification, according to the number of skin lesions present. This classification is due to be used when there is lack of laboratory support or clinical expertise, in which case, the disease will be classified as paucibacillary leprosy or multibacillary leprosy. However, despite useful in certain occasions, this method may lead to misclassification of some patients, resulting in undertreatment of some cases.[4]
This classification allows, however, for a rapid diagnosis, selection and initiation of treatment, according to the class of leprosy:[5]
Paucibacillary or PB
Multibacillary or MB
If a skin smear is done and shows a positive result, then that patient will immediately be classified as a multibacillary patient, irrespective of the number of skin lesions identified on physical examination.
References
- ↑ 1.0 1.1 1.2 Walker, Stephen L.; Lockwood, Dina N.J. (2007). "Leprosy". Clinics in Dermatology. 25 (2): 165–172. doi:10.1016/j.clindermatol.2006.05.012. ISSN 0738-081X.
- ↑ Eichelmann, K.; González González, S.E.; Salas-Alanis, J.C.; Ocampo-Candiani, J. (2013). "Leprosy. An Update: Definition, Pathogenesis, Classification, Diagnosis, and Treatment". Actas Dermo-Sifiliográficas (English Edition). 104 (7): 554–563. doi:10.1016/j.adengl.2012.03.028. ISSN 1578-2190.
- ↑ Bhat, Ramesh Marne; Prakash, Chaitra (2012). "Leprosy: An Overview of Pathophysiology". Interdisciplinary Perspectives on Infectious Diseases. 2012: 1–6. doi:10.1155/2012/181089. ISSN 1687-708X.
- ↑ 4.0 4.1 Pardillo FE, Fajardo TT, Abalos RM, Scollard D, Gelber RH (2007). "Methods for the classification of leprosy for treatment purposes". Clin Infect Dis. 44 (8): 1096–9. doi:10.1086/512809. PMID 17366457.
- ↑ "Enhanced global strategy for further reducing the disease burden due to leprosy (2011-2015)" (PDF).