Discussion
KLC is considered by some to be a variant of lichen planus while others
believe that it has a distinct clinical and histological picture(4). The
combination of lichenoid keratotic papules with a characteristic
linear/reticular arrangement with an erythematous facial eruption refers
to the clinical diagnosis of KLC. The histologic features of KLC are
variable and nonspecific; however, the presence of parakeratosis and
heavier infiltration than what usually seen in lichen planus may help in
differentiation(4).
Although children are occasionally affected, the majority of reported
KLC cases are adults. In 2007 Ruiz-Maldonado et al. studied 14 cases of
pediatric-onset KLC and compared them with adult-onset KLC (3). They
proposed that some features of KLC might characterize pediatric-onset
KLC including an early or congenital onset, a positive family history
with a probable autosomal recessive inheritance, a greater proportion of
male to female, an initial location of lesions on the face with
erythematous-purpuric macules, forehead, eyebrow, and eyelash alopecia,
the higher frequency of pruritus, and a much lower frequency of mucosal
involvement and systemic abnormalities (3). Our patient began to develop
skin lesions during the first year of her life making her a
pediatric-onset KLC but she presented with features more consistent with
those of adult-onset KLC. First, the lesions had appeared on the chest
instead of the face. Indeed, her facial rosacea-like lesions were a
recent phenomenon. Secondly, extensive oral erosions and prominent nail
involvement in our case are other dermatological alterations seen in
50% and 30% of adult-onset patients respectively (3) but occurring
infrequently in children. Negative family history and lack of alopecia
are also in favor of adult-onset disease.
The other less common features of KLC are summarized in Table 1.
KLC has a chronic course with a gradual progression and most cases have
failed to show a favorable response to any treatment with a mean
follow-up time of 14 years in adults(3). Several anecdotal reports have
shown the efficacy of ultraviolet A- and ultraviolet B-light
phototherapies, natural light,
photochemotherapy, and oral retinoids (acitretin or isotretinoin) plus
phototherapy.(3) In our case, the patient showed a partial response to
treatment with acitretin but phototherapy was not feasible due to the
COVID-19 outbreak. Based on the current data systemic corticosteroids,
antimalarial agents, sulfones, gold, and cyclosporine are proven to be
ineffective in the treatment of KLC(4).