Oral lichen planus in childhood.

Oral lichen planus is rare in childhood, and only a few reports on this subject have appeared in the literature. Our objective was to report individual cases of oral lichen planus in childhood from our practice and to review the literature on this subject. We recruited patients younger than 18 years with oral lichen planus and documented several clinical aspects, the histopathology, patch tests, and blood examination findings. Three patients from about 10,000 dermatology patients younger than 18 years seen from 1994 to 2003 were included. Of these three, an Asian girl aged 11 years had an asymptomatic, hyperkeratotic variant of oral lichen planus, which disappeared without any treatment after 1 year. An Asian boy aged 16 years had an erosive oral lichen planus with severe pain, which healed after intensive local and systemic treatment in 2 years. A Caucasian girl aged 14 years had a hyperkeratotic variant with a little soreness, which disappeared with local treatment after 3 months. Our findings indicated that oral lichen planus in childhood is rare and therefore at present it is not possible to draw firm conclusions considering its nature and etiology. Oral lichen planus in childhood seems to occur preferentially in those of Asian race. The clinical features resemble those of oral lichen planus in adults. However, generally the prognosis of oral lichen planus in childhood seems to be more favorable than in adults.

Premalignant nature of oral lichen planus.

The issue as to whether oral lichen planus is a premalignant disorder is still controversial. This study aimed to examine oral malignancies associated with oral lichen planus and to investigate whether oral lichen planus has an intrinsic malignant potential or whether there are also contributing external risk factors. A retrospective cohort study in 200 Caucasian patients with oral lichen planus was conducted between 1991 and 2003. Aspects such as sex, age, clinical variant, affected anatomical sites, duration of the disease, histopathology, prior immunosuppressive treatment, exposure to potential carcinogens and other concomitant diseases were examined. Histopathological examination was repeated during the follow-up if a malignancy was suspected. Three (1.5%) of the 200 patients developed an oral squamous cell carcinoma at the same site following the initial diagnosis of oral lichen planus after a period of 3-6 years (mean 4.3 years). Contributing external risk factors were also noted in two of the three patients (smoking for 20 years and systemic immunosuppressive treatment for 2 years). The exact incidence of malignant transformation is difficult to establish, because of the low number of patients and because of the possible contribution of external risk factors, which may be relevant in oral malignancy.

Oral lichen planus and allergy to dental amalgam restorations.

OBJECTIVES: To determine contact allergies in patients with oral lichen planus and to monitor the effect of partial or complete replacement of amalgam fillings following a positive patch test reaction to ammoniated mercury, metallic mercury, or amalgam. DESIGN: In group A (20 patients), the oral lesions were confined to areas in close contact with amalgam fillings. In group B (20 patients), the lesions extended 1 cm beyond the area of contact with amalgam fillings. In group C (20 patients), the oral lesions had no topographic relationship with amalgam fillings. Partial or complete replacement of amalgam fillings was recommended if there was a positive patch test reaction to ammoniated mercury, metallic mercury, or amalgam. Control group D (20 patients) had signs of allergic contact dermatitis. RESULTS: Amalgam fillings were replaced in 13 patients of group A, with significant improvement. Dental amalgam was replaced in 8 patients of group B, with significant improvement. In group C, amalgam replacement in 2 patients resulted in improvement in 1 patient. These results were evaluated after 3 months. No positive patch test reactions to mercury compounds were found in patients with concomitant cutaneous lichen planus and in group D. CONCLUSIONS: Contact allergy to mercury compounds is important in the pathogenesis of oral lichen planus, especially if there is close contact with amalgam fillings and if no concomitant cutaneous lichen planus is present. In cases of positive patch test reactions to mercury compounds, partial or complete replacement of amalgam fillings will lead to a significant improvement in nearly all patients.

Anti-Mycobacterium leprae monoclonal antibodies cross-react with human skin: an alternative explanation for the immune reponses in leprosy

A panel of 17 mouse monoclonal antibodies (MoAb) raised against Mycobacterium leprae (M. leprae) antigens was used to detect antigenic determinants in normal human skin. An indirect immunoperoxidase technique was used. Eight of the MoAb detected epidermal antigens similar to patterns well known for human sera. Five of these MoAb detected determinants in the dermis, too. These observations may indicate a certain degree of similarity between the antigenic determinants occurring in M. leprae and in the human host. We propose that such a similarity on the one hand may facilitate the survical of M. leprae in the human host when the antigens are not recognized as "non-self", a situation which seems to ocuur in lepromatous leprosy, when the patients' tissues are loaded with bacteria virtually without any immune response. On the other hand, M. leprae antigens which mimic host antigens may induce an auto-immune reaction against the host's own antigens, which could explain the immune reaction in tuberculod leprosy and during a "reversal reaction" when M. leprae is not observed in the host tissues, but extensive granuloma formation occurs