Lichen planus is a disease generally considered uncommon in children. Our objective was to obtain epidemiologic data retrospectively and determine the clinical characteristics of lichen planus in Mexican children seen in our dermatology department. We found 235 patients with the clinical and histologic diagnosis of lichen planus seen over a period of 22 years and 7 months. Twenty-four (10.2%) of these patients were children (15 years of age or younger). The ratio of male to female was 1:1.2. The main clinical pattern was classic lichen planus (43.5%). Mucous membrane and nail involvement were uncommon. No family history of lichen planus or systemic disease was noted. In the international literature, the frequency of lichen planus varied from 2.1% to 11.2% of the pediatric population. In the majority of studies no significant gender predominance was identified. Most patients had the classic variety of lichen planus. Reported mucosal involvement was rare, except in India and Kuwait. Frequency of nail involvement ranged from 0% to 16.6%. Little evidence of systemic disease or family history was found.

This study in a Mexican population sheds light on the frequency and the alterations produced by nail unit tumors, which we must keep in mind for a more accurate diagnosis.

The etiology of lichen planus (LP) is still unknown and previous studies have found an association between LP and HLA-DR1, DR2, DR3, DR9 and DR10 in different populations. The aim of this study was to analyze the distribution of the HLA-DRB1 alleles in Mexican Mestizo patients with LP. The aim of this study was to determine the gene frequency of HLA-DR locus in Mexican Mestizo patients with LP. We studied 20 patients with LP and 99 healthy Mexican Mestizo controls. HLA-DRB1 was performed by PCR-SSO reverse dot blot hybridization. High resolution HLA typing was performed by PCR-SSP. The HLA-DRB1*0101 allele was associated significantly in LP patients compared with healthy controls (pC = 0.0007, OR = 5.46, 95% CI = 1.86-16.06). HLA-DRB1*0101 is a marker for the development of LP in Mexican Mestizo population, yet another gene or HLA marker within MHC region may be the causatively associated gene.

Case 1: A 33-year-old man with a 14-year history of localized skin disease on the face and scalp was evaluated at the department of dermatology. The physical examination revealed plaques with papules, pustules, and a golden yellow crusting on the forehead, cheeks, upper lip, and chin (Figure 1). The scalp presented fine, whitish scales. At the beginning of his disease, the patient presented large red and painful purulent boils. The 14-year clinical course of these lesions was characterized by partial remissions and recurrences, but he did not specify any treatment related to improvement. The clinical diagnosis given for the scalp lesions was seborrheic dermatitis. For the facial lesions, many differential diagnoses were considered, among them: seborrheic dermatitis, acneiform dermatitis, impetigo, folliculitis, seborrheic pemphigus, and demodicidosis. The histopathologic study of a biopsy taken from the cheek (Figure 2) showed superficial spongiform dermatitis with neutrophils and folliculitis that are compatible with the diagnosis of seborrheic dermatitis. Both Gram and periodic acid-Schiff stains were negative. Follow-up of the patient was not possible since he did not come back. The disease in this patient initially manifested at age five by the presence of recurrent ganglionic abscesses. At age 15, he presented a pulmonary abscess of a left lobule that was surgically removed; at this point the diagnosis of chronic granulomatous disease was established. At age 28, an exploratory laparotomy was performed due to peritonitis and multiple hepatic abscesses. At that time, he was treated with antibiotics (mainly trimethoprim-sulfamethoxazole) and interferon-g. The patient had two brothers who died due to complications of chronic granulomatous disease. In addition, both his mother and sister presented a history of discoid lupus-like lesions. Case 2: Coincidentally, his 27-year-old sister was seen in our department of dermatology 5 years before, presenting infiltrated and erythematous plaques with fine scales (Figure 3) on the right side of the nose and the left annular finger. No other cutaneous or mucous lesions were seen. She referred onset in childhood with similar lesions on sun-exposed areas that disappeared without scarring. A biopsy was performed and the results were compatible with the diagnosis of discoid lupus erythematosus (Figure 4). Direct immunofluorescence was not available. At that time, she did not mention the family history of chronic granulomatous disease. Clinical follow-up was not possible, but his brother referred that she afforded complete remission only with sun protection.

No abstract