"Pediatric blaschkitis": expanding the spectrum of childhood acquired Blaschko-linear dermatoses

Area of Science:

• Dermatology
• Pediatrics
• Genetics

Background:

• Blaschko-linear dermatoses are conditions that manifest in patterns along Blaschko lines, which represent lines of cellular migration during embryonic development.
• Lichen striatus is a common acquired Blaschko-linear dermatosis typically seen in children, characterized by papules and plaques.
• Blaschkitis has been described primarily in adults, presenting as pruritic, papulovesicular eruptions along Blaschko lines.

Observation:

• Two young children presented with recurrent, itchy, papulovesicular rashes arranged in distinct bands along their Blaschko lines.
• Skin biopsies from both children showed spongiotic dermatitis, a type of inflammatory skin reaction.
• This is the first documented instance of blaschkitis occurring in pediatric patients.

Findings:

• The findings suggest that blaschkitis and lichen striatus are distinct but related acquired Blaschko-linear dermatoses.
• These conditions may exist on a spectrum, rather than blaschkitis being solely an adult form and lichen striatus a childhood form of a single disease.
• Key features differentiating blaschkitis from lichen striatus were identified.

Implications:

• This report expands the understanding of Blaschko-linear dermatoses in children.
• It prompts further investigation into the pathogenesis, including the roles of cutaneous mosaicism, environmental factors, and immune status.
• The study contributes to defining the spectrum of inflammatory dermatoses that follow Blaschko lines.