What is Lichen Striatus
Lichen striatus is a benign, self-limited T-cell mediated inflammatory dermatosis that presents as a linear band of papules following Blaschko lines, occurring predominantly in children, with spontaneous resolution typically within one year. 1
Clinical Presentation
The condition manifests with a sudden onset of discrete, flat-topped papules that are:
- Skin-colored, pink, erythematous, or violaceous
- Smooth or scaly in texture
- Coalesce to form an interrupted or continuous linear band over days to weeks 1
Key Distinguishing Features
- Distribution: Unilateral and follows Blaschko lines (not dermatomal)
- Sites of predilection: Extremities, particularly lower limbs 2, 3
- Typically solitary with minimal to absent symptoms 1
- In dark-skinned individuals, lesions may be hypopigmented at onset 1
Demographics and Natural History
The condition shows clear epidemiological patterns:
- Primarily affects children, with preponderance in preschool age 4
- Female predominance in most series
- Self-resolves within 4 months to 4 years (median 12 months) 3
- May leave transient post-inflammatory hypopigmentation or hyperpigmentation 1
Nail Involvement
Nail changes occur alone or with skin lesions, presenting as:
- Onychodystrophy
- Longitudinal ridging
- Single nail involvement or partial nail involvement should prompt consideration of lichen striatus 5
- Nail dystrophy often persists longer than skin lesions but eventually resolves completely 3
Pathophysiology
The condition is believed to represent an abnormal immune response to an altered keratinocyte clone after a triggering event 5. The preponderance of cases with spring/summer onset supports a possible environmental or infectious trigger 4.
Management Approach
Treatment is often unnecessary given the self-limited nature 1. When intervention is desired:
- First-line: Low- to mid-potency topical corticosteroids for pruritus or cosmesis 1
- Alternative: Topical immunomodulators (calcineurin inhibitors) 1, 5
- For nail involvement: Intralesional steroid injections may be considered for severe or prolonged dystrophy 5
- For post-inflammatory changes: Fading creams for hyperpigmentation 1
Diagnostic Considerations
- Onychoscopy can help visualize nail changes and avoid unnecessary biopsies 5
- Biopsy should be performed only when diagnosis is uncertain to exclude more serious conditions like lichen planus or nail unit tumors 5
- Histopathology shows perivascular and peri-appendageal infiltration 6
Important Clinical Pitfalls
- Do not confuse with linear lichen planus (more persistent, different histology)
- Distinguish from linear psoriasis (different scale characteristics)
- The distinction between adult-onset lichen striatus and "adult blaschkitis" is clinically unnecessary given overlapping features 6
- A possible association with atopy has been observed 2, 3