Linear psoriasis: case report on three year old child

Abstract

Atypical and unusual locations of psoriasis are very frequent. However, localized linear psoriasis is rare, with few cases described in the literature. It is characterized by a linear distribution of psoriasis lesions along Blaschko lines. We report the case of a three years old child, who presented unilateral erythematous scaly plaques arranged along Blaschko lines in the left hemithorax, with no associated symptoms and no lesions in other parts of the body. The differentiation of linear psoriasis from other linear dermatoses is not easy. The combination of a thorough history, a careful examination of the skin and histopathology are essential to ensure the correct diagnosis and appropriate treatment.

FIGURE 1

Erythematous, scaly plaques, following linear path in the left hemithorax

FIGURE 2

Histological image (400x): epidermis shows pattern of psoriasiform acanthosis associated with hypo-agranulosis and parakeratotic hyperkeratosis. Accompanying superficial perivascular lymphocytic inflammation

FIGURE 3

Histological image (400x): Epidermis shows psoriasiform acanthosis associated with hypo-agranulosis and parakeratotic hyperkeratosis. Accompanying superficial perivascular lymphocytic inflammation

FIGURE 4

Hypopigmented residual spot along Blaschko lines in the left hemithorax after topical treatment with clobetasol 0.05%