Hansen's disease in Childhood

Hansen's disease in children under fifteen years old and its consequences have been the subject of study by several authors and international bodies. There are numerous case reports of the disease in this age group, which represent increases in the transmission chain of the bacillus in the community and deficiencies in surveillance and control of the disease.^(1,2,3) Hansen's disease in childhood is both a public health problem and one of the most sensitive indicators of early exposure, persistence of transmission in the community and limited effectiveness of control programmes. Detection in this age range is taken as an indicator of greater severity of endemic disease. In endemic countries, the child population comes into early contact with people affected by Hansen's disease, and detection of the disease is frequent among children between three and five years of age; fortunately, cases are rarely observed in under-2s, mainly in the virchowian form.^(4,5) There are differences in prevalence between regions, states, micro-regions, and municipalities, focused on places of greatest poverty and having a close relationship with precarious housing conditions, low school attendance, and migratory movements that facilitate the spread of the disease.

Hansen's disease is a chronic infectious disease that predominantly affects the skin and peripheral nerves. The diagnosis is essentially clinical and epidemiological, being performed through anamnesis and dermatoneurological examination. In childhood, the diagnosis requires careful examination due to the difficulty of performing and interpreting tests. The clinical signs of Hansen's disease are often not easy to recognize in childhood.⁽⁵⁾ The young age of these patients is a limiting factor, although in some endemic regions the number of children with Hansen's disease-induced deformities is high. ⁽⁶⁾ Studies on Hansen's disease identify the number of boys affected by the disease being higher than that of girls, although there is no biological evidence that males have lower resistance to the disease. High endemicity of the disease in one area will provide multiple exposures of the population to the bacillus, as well as being a source of exposure in the first years of life. One hypothesis is that boys are generally exposed to more frequent and intense social interactions compared to girls. ⁽⁷⁾

Hansen's disease has a curative treatment. However, if at the time of diagnosis, the patient has already developed a physical deformity, it may become a permanent disability. In childhood, Hansen's disease is potentially disabling because this is a period of growth and development. Social, physical and psychological problems arising from childhood Hansen’s disease compromise the future wellbeing of affected children. ⁽⁸⁾ This was addressed in a recent study that investigated the association between low motor skills and school activities and the presence of physical changes resulting from Hansen's disease.⁽⁹⁾ The social issue is evidenced by the high number of people affected as a result of intrafamily transmission and the avoidance of disclosure to people outside the family about the treatment of the child affected by Hansen's disease.⁽¹⁰⁾ Affected children generally have their routines altered by the limits of the disease and treatment.

Hansen's disease presents a variety of clinical manifestations that are related to the patient's immunological conditions and its relationship with M. leprae. Most children diagnosed with Hansen's disease are classified as paucibacillary (PB), although the WHO has been warning of an increase in multibacillary (MB) Hansen’s disease cases. ⁽¹¹⁾ Some studies have already indicated a predominance of the MB form in some endemic regions.^(12,13) Generally, children are intradomiciliary contacts, especially among those living with MB patients. As with all diseases with a long incubation period, there is an increase in cases as age progresses. ⁽¹⁴⁾ A low frequency of the disease in children under 5 years of age, an increase in the number of cases with age and an almost equal distribution of cases in the 5-10 years and 10-15 years age groups are often observed. ⁽¹⁵⁾

The detection rate of new cases in children under 15 is directly related to the level of endemicity and reflects early exposure to M. leprae.⁽¹⁶⁾ Therefore, the study of Hansen's disease indicators in this age group is necessary to know the magnitude and strength of the endemicity and the performance of the health system in surveillance of the disease. The close relationship between early detection and timely access to the health system as a means of helping to prevent and stop the progressive deformity due to Hansen's disease is also known.⁽¹⁷⁾ Incorrect or delayed diagnosis causes more problems for the affected child.⁽¹⁸⁾ Incorrect diagnosis caused by errors in the differential approach to diagnosing other dermatological or neurological diseases may be one of the reasons for the excessive number of cases reported in children.

The clinical picture can be as varied as in adults. Most children have fewer than three lesions at the time of diagnosis, and many have only macular skin lesions. The nodular form in childhood is frequently seen and is described in the chapter on clinical aspects of Hansen’s disease. Around 5-20% of children with Hansen's disease will have episodes of reaction (exacerbation of inflammatory, localized or systemic processes) at some time before, during and/or after the end of multidrug therapy (MDT).⁽¹⁹⁾ Complications associated with reactional episodes of Hansen's disease or due to prolonged use of corticosteroids in treatment are also observed.⁽¹⁹⁾ Complementation of the diagnosis by histamine and pilocarpine tests or histopathology are often used. The need for the test in people with Hansen's disease to be extended to the oral mucosa is also indicated, as this can be a secondary source of transmission and infection by M. leprae.⁽²⁰⁾

In view of the seriousness of Hansen's disease in children under the age of 15, strict control involving epidemiological surveillance should be maintained in children at risk for Hansen’s disease through intradomiciliary contact. ⁽²¹⁾ The proportion of new cases of Hansen's disease in children under 15 is used to measure and monitor active and recent transmission,^(22,23) It is an important indicator of the occurrence of Hansen’s disease in a community and of the effectiveness of health programs.⁽²⁴⁾ According to Sundharam, the physical examination of children under 15 years old can be impeded by the refusal of children to undress, or by the difficulty of communication with health professionals.⁽²⁵⁾ In Brazil, for example, the state of Pará registered 2,562 new cases of infection in 2017, 9% of which involved children, thereby revealing problems in controlling the disease.⁽²⁶⁾ The dissemination of the signs and symptoms of the disease to the general population is an additional tool for reducing endemicity.^(27,28,29)

More specific prevention and control measures aimed at children younger than 15 years old could also be adopted, including active searching in schools and day care centres and lessons clarifying the signs and symptoms of the disease. Evaluating new strategies of health education focusing on Hansen's disease is also important, such as self-examination among children capable of doing so. With these practices, the detection of new childhood cases and their early treatment can be increased, generating a break in the chain of transmission.

It is important to extend prevention measures to regions where Hansen's disease has been technically eliminated, to prevent its re-emergence.⁽³⁰⁾