What is This Nonpruritic Rash?

Lichen striatus is a benign self-limited dermatosis of unknown etiology. It is characterized by a linear inflamma- tory papular eruption and is seen primarily in children.1 Synonyms for lichen striatus include lichenoid trophoneu- rosis, zonal dermatosis, linear neurodermatitis, and neuro- dermite zoniforme. 2

EPIDEMIOLOGY

Lichen striatus typically affects children between ages 5 and 15 years.3 The condition has occasionally been described in infants and adults.4,5 The female-to-male ratio is approximately 2:1.6 There is no known racial variation in incidence. The condition is more common in the spring and summer.7 Approximately 85% of patients with lichen striatus have a personal or family history of atopy.8

Lichen striatus usually occurs sporadically.1 Simulta- neous familial occurrences have rarely been described.7,9

HISTOLOGY

The histology is that of a chronic dermatitis.6 A peri- vascular lymphocytic and histiocytic infiltrate in the superficial and deep dermis is characteristic. Spongiosis, exocytosis, hyperkeratosis, and parakeratosis may also be seen.9,10

CLINICAL MANIFESTATIONS

The onset is usually abrupt. The eruption consists initially of discrete, flesh-colored or pink, flat-topped papules, 1 to 3 mm in diameter.3-10 Papules often coalesce to form a hyperpigmented continuous or interrupted lin- ear band.6-11 In dark-skinned persons, the lesions may be hypopigmented. Although lichen striatus may involve any part of the body, the arms and legs are most commonly af- fected.3 Rarely, the lesion is seen on the penis.5

Typically, the lesion is solitary, unilateral, and follows Blaschko lines (the cutaneous lines of embryogene- sis).2,4,6,11,12 Occasionally, the lesion may extend over the entire length of an extremity.11 The lesion is usually asymptomatic and nonpruritic.2 Rarely, onychodystrophy may occur, especially when the eruption involves the pos- terior nail fold and matrix.3,13 Nail involvement may pre- cede the development of the skin lesion.3,13

DIFFERENTIAL DIAGNOSIS

The differential diagnosis includes lichen planus, linear psoriasis, linear epidermal nevus, inflammatory lin- ear verrucous epidermal nevus, allergic dermatitis, and

atopic dermatitis. Both lichen planus and linear psoriasis are usually associated with typical individual lesions else- where on the body. In addition, the lesion of lichen planus is usually intensely pruritic, tends to be larger, violaceous, and is often quite hypertrophic.3 The lesion of linear epidermal nevus usually appears in early infancy and does not regress.1,3 With time, the lesion becomes more kera- totic and hyperpigmented than that of lichen striatus.

The lesion of inflammatory linear verrucous nevus tends to be extensive and is markedly pruritic.1,3 The lesions of allergic dermatitis and atopic dermatitis are typically pruritic. ■

Treatment

Lichen striatus is a self-limited condition that often resolves within 1 year.1,11 When associated with onychodystrophy, the lesion tends to persist longer.3 For those patients who want therapy for cosmetic reasons, a topical corticosteroid is the treatment of choice because it may hasten resolution of the lesion.7

REFERENCES:
1. Hauber K, Rose C, Bröcker EB, Hamm H. Lichen striatus: clinical features and follow-up in 12 patients. Eur J Dermatol. 2000;10:536-539.
2. Taieb A, el Youbi A, Grosshans E, Maleville J. Lichen striatus: a Blaschko lin- ear acquired inflammatory skin eruption. J Am Acad Dermatol. 1991;25:637-642. 3. Karp DL, Cohen BA. Onychodystrophy in lichen striatus. Pediatr Dermatol. 1993;10:359-361.
4. Mitsuhashi Y, Kondo S. Lichen striatus in an adult. J Dermatol. 1996;23:710-712. 5. Hofer T. Lichen striatus in adults or ‘adult blaschkitis’? There is no need for a new naming. Dermatology. 2003;207:89-92.
6. Kanegaye JT, Frieden IJ. Lichen striatus: simultaneous occurrence in siblings. Pediatrics. 1992;90:104-106.
7. Krafchik BR, Halbert A, Yamanoto K, et al. Lichen striatus. In: Schachner LA, Hansen RC, Happle R, et al, eds. Pediatric Dermatology. Edinburgh: Mosby; 1995: 641-642.
8. Toda K, Okamoto H, Horio T. Lichen striatus. Int J Dermatol. 1986;25:584-585. 9. Zhang Y, McNutt NS. Lichen striatus. Histological, immunohistochemical, and ultrastructural study of 37 cases. J Cutan Pathol. 2001;28:65-71.
10. Patrizi A, Neri I, Fiorentini C, et al. Simultaneous occurrence of lichen stria- tus in siblings. Pediatr Dermatol. 1997;14:293-294.
11. Goyal S, Cohen BA. Lichen striatus. Arch Pediatr Adolesc Med. 2001;155: 197-198.
12. Vasily DB, Bhatia SG. Lichen striatus. Cutis. 1981;28:442-446.
13. Goskowicz MO, Eichenfield LF. Onychodystrophy with lichen striatus. Pediatr Dermatol. 1994;11:282-283.