Lichen planus and nephrotic syndrome--coincidence or causation?

We describe an 8 year old boy who presented with lichen planus (LP) and minimal change nephrotic syndrome (MCNS), and discuss the possible pathogenetic links between the two disorders. A 7 year old boy presented with anasarca for 7 days in association with skin lesions over both the lower limbs. The skin lesions were bilaterally symmetrical violaceous polygonal pruritic papules present over both lower limbs, diagnostic of classical LP; and appeared simultaneously along with periorbital edema progressing to anasarca. The oral, genital mucosa and nails were unaffected. There was no causal relationship of either the skin lesions or anasarca with any drug usage or immunization. There was no jaundice, hepatosplenomegaly, lymphadenopathy or joint involvement. Urinalysis showed proteinuria (urine spot protein: creatinine ratio 3.4). Serum albumin and cholesterol were 1.8 g/dL and 340 mg/dL respectively. Serum creatinine was 0.5 mg/dL. Hepatitis serology profile, chest x-ray and complete blood counts were normal. Anti-nuclear antibody (ANA) were negative and C3 levels were normal. The renal biopsy showed minimal change disease. He was treated with prednisolone as per standard guidelines [1], and went into remission. The skin lesions were treated with 0.05% betamethasone dipropionate cream for 2 weeks and healed with patchy hyperpigmentation. Seven months later, he had a relapse of nephrotic syndrome coincident with flare of the lichenoid lesions over the same sites. He was again treated with systemic and topical steroids. Proteinuria is currently settled. Itching has subsided, however residual postinflammatory hyperpigmentation is present.