Leprosy reactions: the effect of gender and household contacts

Abstract

Although leprosy is a chronic infectious disease, it may be considered an immunologic disease too (Lupi et al. 2006, Naafs 2006. In fact, a noticeable proportion of leprosy patients suffer from immunologic hypersensitivity reactions at any given time in the disease process, including before, during and after treatment. These adverse immunological reactions are now the most significant issue in the management of leprosy.There are two primary types of leprosy reaction: (i) type 1 reaction: also called reversal reaction occurs only in patients with borderline disease and is associated with oedema, increased erythema, potential ulceration of existing skin lesions and nerve damage, which is the major concern and (ii) type 2 reaction: also called erythema nodosum leprosum, is a systemic inflammatory response which may manifest in fever, arthralgias, myalgias, anorexia, erythematous sparse tender nodules on the extensor surfaces of the extremities. Conjunctivitis, neuritis, keratitis, iritis, synovitis, nephritis, hepatosplenomegaly, orchitis and lymphadenopathy may also occur. Although several new drugs have been studied and found to be of some use, corticosteroids continue to be the mainstay treatment in the management of leprosy reactions. Unfortunately, the chronic administration of corticosteroids induces either minor (moon face, severe fungal skin infections, severe acne and gastric pain needing antacid) or major side effects (psychosis, peptic ulcer, glaucoma, cataracts, diabetes, hypertension and steroid dependency) resulting in permanent damage.Various host-related factors have been reported as risk factors for leprosy reactions, such as female gender, pregnancy and breastfeeding, suffering from lepromatous leprosy, presence of a positive bacterial index, undergoing multi-drug therapy for leprosy, other medications, vaccinations, infections, injury and physical and mental stress (review in Mastrangelo et al. 2008). It has been reported that these factors are presumed to cause the multiplication of dormant viable Mycobacterium leprae (which are known to persist for many years in Schwann cells or in fibrous tissue without producing any ill effects) and the release of microbacterial antigens in the local tissues (Britton & Lockwood 2004).In endemic areas, it was found that: M. leprae survives outside of the human body, healthy individuals harbour M. leprae bacilli in the nasal cavity and microorganisms can be subsequently released into the environment and there is widespread subclinical transmission of M. leprae with transient infection of the nose resulting in the development of a mucosal immune response (review in Mastrangelo et al. 2008).

Clinical variables associated with leprosy reactions and persistence of physical impairment

“…The morbidity associated with leprosy is related to multiple skin lesions observed in MB forms 11 , leprosy reactions 12 , and physical impairment 13 , which are the disease's primary complications. It is important to identify the clinical characteristics that can predict these deleterious outcomes.…”

“…Early identifi cation combined with the proper treatment of leprosy reactions can be an effective strategy to prevent physical impairment in leprosy 13,14 . Prednisone is the drug of choice not only for the treatment of leprosy reactions and silent neuritis events 21 but also to reduce swelling and prevent further physical impairment 18 .…”

Can studies where subjects have different follow-up times be analysed through binomial regression?

“…As it uses the binomial distribution family, the heading "binomial regression" is appropriate. However, it differs from the model used by Mastrangelo et al (2011) in that it yields rate ratios rather than risk differences. Penna (2011) and Alexander (2011, this letter) discuss the use of logistic regression for the analysis of incidence data.…”

“…This is a useful approach when the exact time of the event is unknown. This method for data analysis was not conducted by Mastrangelo et al (2011). Both Penna (2011) andAlexander (2011) are correct in their comments, which contribute to a better understanding as to the appropriate use of statistical models and the best possible use of available data.…”

“…Penna (2011) and Alexander (2011, this letter) discuss the use of logistic regression for the analysis of incidence data. The motivation is taken from Mastrangelo et al (2011), who used logistic regression to assess the effect of gender and household contacts as they relate to the risk of leprosy reactions. The study population was comprised of leprosy patients in treatment from 1998-2005.…”