Introduction
The exact aetiology of lichen planus still remains a mystery, the possible factors implicated include T cell mediated auto immune reactions, genetic factors, bacterial or viral infections, drug intake, liver disease and psychogenic factors.1
In the past few years, lichen planus has been linked to hepatitis C virus (HCV) infections, with studies demonstrating a higher prevalence of anti HCV antibody titers in patients with cutaneous and oral lichen planus. However there are geographical variations in the reported prevalence of HCV infection in patients with lichen planus varying from 0% in England to 63% in Japan.2
The association of lichen planus with hepatitis C and hepatitis B infections is not studied extensively in this part of our country. The prevalence of cutaneous and oral lichen planus in this region is considerably high. Hence, a clinical study of lichen planus with special reference to its association with hepatitis C infection is worth undertaking.
Materials and Methods
The study was designed to be an observational, hospital based case control study conducted in a tertiary care hospital. The study group comprised of 100 cases of clinically and histopathologically diagnosed subjects of lichen planus and an equal number of age and gender matched healthy controls. The study was conducted between January 2014 and October 2015 after obtaining institutional ethical committee clearance. A detailed history and clinical examination was performed and the data was recorded in a proforma. The serum of both the group was examined for presence of HCV antibodies using a visual, quantitative, highly sensitive and specific 4th generation HCV tridot test. Among the cases, those who had drug induced lichen planus, chronic infections and dental filling were excluded. The data was compiled in Microsoft excel and was analyzed using SPSS2.0 version software. Qualitative data was represented by percentage and frequency test. HCV antibody frequency was compared in both groups using Pearson’s Chi square test.
Results
Among the cases, the most commonly observed age group was between 30-39 years (33%) with a mean of 34.67 and median age of 25.5 (Table 1). The youngest patient was 13 years old and the oldest 69 years. The female to male ratio was 3:2 with 60% females and 40% males.(Figure 1). The duration of lichen planus in majority of the cases was between 1 to 6 months with a mean of 3.34 months. The shortest duration was of 1 week and the longest was 5 years.
The most commonly observed morphological type of lichen planus was the classical variety (58%), (Figure 2) followed by hypertrophic (16%), (Figure 3) and annular variety (5%), (Table2). Involvement of oral mucosa was observed in 18 patients. Within the oral mucosal lesions reticular morphology was seen in 50%, (Figure 4), papules in 22.22% and plaque and atrophic types observed in 11.1% and 16.6% respectively. The genital mucosa was not afflicted in any of the cases. Nails were involved in the form of beau’s lines in 3 patients and alternate dark and white longitudinal lines in 2 patients.
The serum of both the cases and the controls were screened for HCV antibodies using a 4th generation tridot test. It was observed that in both the groups the HCV antibody test was not detected in any individual (P value- 0.023) which was statistically significant. The value of the Pearson’s Chi square test was zero which was statistically not significant to suggest any association.
S
Table 1
Showing age distribution of cases
| Age in years | Frequency | Percentage |
| 10-19 | 3 | 3 |
| 20-29 | 33 | 33 |
| 30-39 | 39 | 39 |
| 40-49 | 14 | 14 |
| 50-59 | 6 | 6 |
| 60-69 | 5 | 5 |
| Total | 100 | 100 |
Table 2
Showing percentage of morphological types of LP andseropositvity
Discussion
The association of lichen planus with HCV infection was suggested for the first time in the year 1991 by Mokni M et al.3 Several studies have described a high prevalence of hepatitis C infection in patients with lichen planus.4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 Other studies have noted a significant association of oral lichen planus with hepatitis C. 14, 15, 16, 17, 18 But there are studies which contradict these views. Studies conducted in India by Narayan S et al, Irshad M et al. Das et al, Prabhu S et al have failed to demonstrate statistically significant association between HCV and lichen planus similar to the findings in the present study. 19, 20, 21, 22
The association of HCV antibodies in lichen planus patients is reported to vary from one geographical area to another. An epidemiological association of lichen planus with hepatitis C infection has been recorded, especially in patients from Italy, certain parts of France, Spain, Japan and Pakistan while no association has been noted in patients from Northern Europe including the UK. USA or Nepal 19, 23, 24 It has been suggested that the observed geographical differences with regard to HCV infection and lichen planus could be related to immunogenetic factors such as the HLA –DR6 allele, significantly expressed in Italian patients with oral lichen planus and HCV infection.
In the present study none of the patients with lichen planus were seropositive for hepatitis C antibodies. The control group also was negative for hepatitis C antibodies. This study thus suggests that the prevalence of hepatitis C antibodies in the general population in this geographical area is low and that the patients with lichen planus do not have an increased prevalence of hepatitis C antibodies in their serum.
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