Leprosy is a chronic infectious disease caused by Mycobacterium leprae. The disease usually affects the skin and peripheral nerves.1 Multidrug therapy was implemented in 1985, impacting the global prevalence of the disease, but transmission of leprosy still occurs. A total of 204,000 new cases are reported each year worldwide, although multidrug therapy was considered to be a tool that would help achieve eradication by the year 2000.1
Leprosy in Colombia is not considered a public health problem because the prevalence is only <1/10,000,2 but the figures are not an accurate reflection of the problem with respect to population distribution.3
In Colombia, 300–500 new cases of leprosy are reported per year. Seven percentage of the new leprosy cases occurred in children <15 years of aged, and 59% of these cases are in children 10–14 years of age.4 This report describes 12 cases of Colombian children with leprosy, who were studied by our research group between 2008 and 2011.
Table 1 shows demographic and clinical data for the 12 patients (age, duration of symptoms, Calmette-Guérin bacillus vaccination, antecedents of leprosy contact, treatment and diagnostic tests performed to confirm the disease). In summary, 3 patients <10 years of age and 9 patients between 10 and 17 years of age were diagnosed. Five cases were classified as paucibacillary (PB) and 7 cases as multibacillary (MB). By definition, all of the PB cases had a bacillary index (BI) = 0; the MB patients had BI varying from 1 to 3. Information about Calmette-Guérin bacillus vaccination was obtained in 11 cases, and 5 had not received the vaccine. With regard to the origin of the disease, 10 were from high endemic regions of the country (Cartagena, Bolivar State, n = 4; Santander State, n = 3; Agua de Dios, Cundinamarca State, n = 2) and the remaining 3 were from a low endemic leprosy region (Antioquia State). The duration of the clinical symptoms ranged from 6 months to 5 years. With respect to the clinical assessment at diagnosis, 5 patients had hypochromic patches while the other 5 children had hyperchromic patches. Six patients had hypoesthesic areas, 3 patients had nodules and 1 had a painless ulceration. Two patients had leprosy reaction. For diagnostic testing, polymerase chain reaction (PCR) for M. leprae DNA was tested in 9 patients (7 MB and 2 PB), and all were positive. IgM anti-PGL1 antibody levels were determined in 7 patients, of which 5 were positive; those patients with both positive and negative antibody levels had positive PCR results.
In 4 cases, histopathology confirmed PB leprosy. Antecedents of contact with leprosy were documented in 10 patients. Finally, we could confirm that 7 patients showed a resolution of symptoms after treatment completion.
Leprosy presents as a broad clinical spectrum; the polar forms are lepromatous (LL) and tuberculoid (TT). TT is the most benign form, characterized by <5 flat or slightly raised skin lesions that can vary in size, are typically pale or slightly red, dry, hairless and numb to the touch (anesthetic) and with few bacteria in the skin and nerve. LL is at the other end of the spectrum, with diffuse involvement of the skin, thickening of the peripheral nerves and, in severe cases, there is involvement of other organs, such as the eyes, nose, testicles and bone; large numbers of bacteria in the skin are characteristic of this clinical outcome.1
There are also intermediate subtypes that are commonly known as borderline leprosy. They are a more extensive disease than TT, with >5 skin lesions and nerve involvement, but not as widespread a disease as LL. Indeterminate leprosy refers to a very early form of leprosy that consists of a single skin lesion with a slightly diminished sensation to touch. Indeterminate leprosy will usually progress to 1 of the polar types of leprosy.3
In 1982, the World Health Organization proposed a classification according to the BI in skin slit samples. PB is defined as having a BI = 0 and MB has a BI > 0. This classification is now used worldwide for treatment purposes. The PB classification encompasses indeterminate, TT and borderline tuberculoid leprosy. The MB classification includes borderline-borderline, borderline lepromatous and LL. It is accepted that MB patients are the most significant source of transmission.1,5
Children are more susceptible to acquire an infection than other family members; approximately 60% may develop the disease.6 Although the incubation period is prolonged, there is evidence that placental transmission of M. leprae can occur rarely, which may explain some reports of childhood leprosy even in infants <1 year of age.6,7 Most of the cases of leprosy in children report a history of familiar contact. In our report, 9 (75%) patients had previous leprosy contact within their household, meaning that the extended family was the documented leprosy contact. Therefore, active surveillance in the community is extremely important to find the possible source of infection or index case.8
According to Cortes et al,4 the MB form is more frequent in patients >15 and is slightly less frequent than the PB form (44% vs. 56%, respectively). Current reports show similar frequencies as 58% of patients with the MB form are >15.
The disease must be suspected when there are single or multiple hypochromic macules or plaques. Changes in sensitivity are difficult to evaluate in children; indeed, the younger the child is, the more difficult the changes in sensitivity are to evaluate.8 Usually, the lesions are few and atypical and more frequent in exposed areas.8,9 Indeterminate leprosy cases show high rates of spontaneous healing.4
The current patients were studied under a research project that used complementary tests that are not available in the leprosy control program: IgM anti-PGL1 and PCR. Because clinical diagnosis in children is difficult, these tests and histopathology are useful to confirm and classify the disease.4
Disability is higher with increasing age in children with leprosy, as the social and psychological effects and stigma of the disease are distressing.10 Although leprosy reactions are uncommon in children, the reactions produce most of the neural damage related to the disease,11 causing disabilities that can lead to a decreased quality of life. Previous reports have found an incidence of 6–30% of leprosy reactions in children,8,12 and we found 2 patients with leprosy reactions (18%) in our study. Another factor that increases disability in patients is the lack of a timely and early diagnosis of the disease.5 We studied children whose symptoms evolved over 6 months to 5 years without a confirmed diagnosis. This fact may be due to a deficient leprosy control program and a lack of clinical training in diagnosing this disease.
Leprosy in Colombia is considered to be in a postelimination phase,13 but leprosy in children is an important epidemiological alert and can be considered an indicator of the prevalence in the general population, as a sign of ongoing transmission.14,15
The authors want to recognize the collaboration of the Sanatorios de Agua de Dios and Contratación and the regional leprosy programs of the departments of Santander, Antioquia and Bolívar.
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11. Cuevas L, De la Hoz F, León C, et al. Caracterización Clínica y Sociodemográfica de Casos Nuevos de Lepra en Municipios Endémicos y no Endémicos de Colombia. Salud pública. 2004;6:10
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13. Cardona-Castro N, Beltrán-Alzate JC, Manrique-Hernández R. Survey to identify Mycobacterium leprae-infected household contacts of patients from prevalent regions of leprosy in Colombia. Mem Inst Oswaldo Cruz. 2008;103:332–336
14. Norman G, Joseph GA, Udayasuriyan P, et al. Leprosy case detection using schoolchildren. Lepr Rev. 2004;75:34–39
15. Imbiriba EB, Hurtado-Guerrero JC, Garnelo L, et al. Epidemiological profile of leprosy in children under 15 in Manaus (Northern Brazil), 1998-2005. Rev Saude Publica. 2008;42:1021–1026