LP is a relatively common disease in adults. The overall prevalence is believed to be somewhat less than 1 percent of the general adult population. It is less common in children1
. Population-based epidemiologic data on the prevalence of LP in children are not available and only a few groups have published series of childhood LP cases that include more than 15 patients2,3,5,6
. As in the adult population, the classical variant of LP with a localized cutaneous lesion was the most common clinical type (58~70%) in pediatric LP patients as well, whereas mucosal and nail involvement was detected to a far lesser extent2,4
. According to the literature, involvement of the palms and/or soles in LP is uncommon, and mainly appears between the third and fifth decade1,7
. The involvement of the palms and/or soles in LP is even more uncommon in the pediatric age group. Recently, Handa and Sahoo3
found 2 cases (2.3%) of LP with palmoplantar involvement in their study of 87 children with LP. Our patient showed generalized LP with palmoplantar involvement, a less frequent clinical subtype with only a few reports of affected children published to date.
The palmoplantar lesions do not usually have the classically described clinical morphology, making it difficult to diagnose. Several morphological patterns of palmoplantar lesions in LP have been described: erythematous plaques, punctate keratosis, diffuse keratoderma and ulcerative lesions. The apparent absence of Wickham's striae may be because the thickness of the horny layer obscures observation of the localized thickening of the granular layer, which is the histopathological correlate of these structures. The palmoplantar LP showed a characteristic histopathology, very similar to that described for other sites. As the clinical features may not suggest LP, a biopsy is extremely useful7
Various precipitating factors are known to play an important role in the pathogenesis of LP. These include drugs, vaccinations and viral infections. A possible role of infection and vaccination in triggering LP has been repeatedly suggested over the years, in particular chronic active hepatitis C infection and immunization against hepatitis B virus1,2,4
. However, no obvious precipitating factors could be elicited in our patient.
To date, due to a lack of controlled clinical trials, no consensus exists regarding standardized therapy regimens for generalized LP in childhood. Still, effective treatment of this highly pruritic skin condition is mandatory to effectively suppress pruritus and to quickly restore quality of life. A short course of systemic steroids has been used in children to control eruptive, widespread disease. Psoralen and ultraviolet A (PUVA) light photochemotherapy and narrowband UVB have been successfully used in adult LP patients1,4
. A recent clinical report indicates that topical tacrolimus might be an effective treatment alternative in the management of patients with generalized lichen planus8
To the best of our knowledge, ours is the first report of a case of childhood LP with palmoplantar involvement in Korea. LP should be considered in the differential diagnosis of polygonal papules and plaques on the whole body including palms and/or soles. Considering the great number of LP variants, clinicians should distinguish childhood LP from other papulosquamous skin diseases such as lichen nitidus, lichen striatus, childhood papular acrodermatitis, and pityriasis lichenoides.