Understanding the type 1 reactional state for early diagnosis and treatment: a way to avoid disability in leprosy

Abstract

A type 1 reaction or reversal reaction is expressed clinically by inflammatory exacerbation of the skin lesions and nerve trunks, consequently leading to sensory and motor alterations. It occurs in non-polar forms of leprosy, although it can occur in a small percentage of sub-polar LL treated patients. Disabilities, deformities and morbidity, still present in leprosy, are mainly caused by these acute episodes. The recognition of reactional states is imperative for an early approach and efficient management, to avoid the emergence of disabilities that stigmatize the disease. This review aims to describe the clinical aspects, immunopathogenesis, epidemiology, histopathological features and therapeutics of type 1 reactions.

Leprosy Reactions

“…The patients may present with the symptoms of neural dysfunction such as loss of sensation, facial palsy, claw hand, and drop-foot. Hyperesthesia may occur in palmar and plantar areas, associated with widespread nerve damage [1]. The ability to close eyelids is lost due to damage in the facial nerves (lagophthalmos) [10].…”

“…The risk of type 1 reaction may increase with vaccination, MDT, pregnancy, puerperality, infections, stress, trauma, and oral contraceptive use. The extensiveness of skin lesions has been described as an important risk factor both in patients with low and high bacilli load [1]. It has been shown that the risk of developing neural damage, along with the risk of developing reversal reaction, is 10-fold higher in patients in whom three or more body segments are affected [11].…”

“…Although factors which can induce type I reactions are not clearly known, recent studies have pointed to genetic factors [5]. Identification of the risk factors, therefore, allows more meticulous follow-up of patients and early treatment [1].…”

“…Sudden changes in immune-mediated response to Mycobacterium leprae antigen are referred to as leprosy reactions. The reactions manifest as acute inflammatory episodes rather than chronic infectious course [1]. These reactions account for about 30-50% of cases with leprosy [2].…”

Environmental toxicant exposure and Parkinson’s disease: LRRK2 and inflammatory processes

“…Indeed, in the case of leprosy, LRRK2 appears to be protective from developing symptoms, however, patients are at much greater risk for an excessive pro-inflammatory response known as type-1 reaction which follows the cessation of disease treatment in some cases [64]. This reaction leads to damage in peripheral nerves and accounts for much of the sensory and motor impairments resulting from the disease [94]. Amongst the numerous disease associated with LRRK2 mutations, a common theme is the role of inflammation, spanning across disease states and organ systems.…”