Unilateral lichen striatus with bilateral onychodystrophy

ARTICLE

Auteur(s) : Firas A Al-Niaimi, Neil H Cox

Department of dermatology, Cumberland Infirmary, Newtown Road, Carlisle CA2 7HY, UK

Lichen striatus (LS) is a linear dermatosis of unknown aetiology, first identified by Senear and Caro. Clinically it presents as scaly papules which may coalesce to form lengthy streaks [1, 2]. We present 2 cases of LS associated with bilateral onychodystrophy.

A 9-year-old girl (patient 1) presented with a 3-month history of an asymptomatic linear dermatosis. Clinically this consisted of papules in a linear arrangement, extending down the posterior aspect of the left lower leg to the arch of the foot with a small area affecting the middle toe. The appearance was typical of LS. A month later she started noticing nail changes in most of her toenails bilaterally (figure 1). Nail clippings were negative for fungi. No treatment was required, it resolved spontaneously within 6 months. The nail changes persisted for some months after the clearance of the eruption but returned to their normal state within 9 months.

A 53-year-old man (patient 2) presented with a 7-month history of a linear dermatosis affecting the anterior aspect of his right lower leg. At the same time he developed bilateral onychodystrophy affecting most of his toenails. Likewise, the diagnosis of LS was made. Fingernails were unaffected and toenail clippings excluded any fungal infection. The toenail changes disappeared within 3 months after the spontaneous resolution of the dermatosis.

Histology from both patients was in keeping with LS. Nail biopsies were not performed in view of the lack of symptoms or pterygium and the spontaneous improvement.

Nail involvement in LS is relatively uncommon and has been linked with adjacent skin involvement at the proximal nail fold; however involvement of many nails, as in the cases of our patients, has also been found, the mechanism of which remains unclear. Remarkably, our patients had bilateral onychodystrophy despite the occurrence of unilateral LS. This may be due to a circulating antigenic trigger affecting the skin and nail matrix. According to Tosti et al. nail involvement can be present in the absence of typical LS skin lesions [3]. Nail changes in LS can appear before, simultaneously with, or after the onset of skin LS, often regressing spontaneously [2, 3].

The aetiology of LS remains unclear but a viral cause has been postulated, based on the self-limiting nature, relatively high prevalence among children, the seasonal variation and the occurrence of both skin lesions and isolated onychodystrophy in siblings. Furthermore, a case of simultaneous LS in siblings did have a specific symptomatic event of a flu-like fever 10 days prior to the onset of LS [4].

LS follows Blaschko’s lines in many of the reported cases, leading to the theory that mosaicism is involved. Taieb et al. suggest that an aberrant clone of epidermal cells produced by somatic mutations migrated out along Blaschko’s lines. Once triggered (e.g. by a virus), a previous tolerance to the clone could be interrupted through the production of membrane antigen(s) [5].

It is postulated that similar triggers affect the nail matrix, leading to the dystrophic appearance of nails in LS. The timescale between the skin appearance and nail changes, with the subsequent clearance of nail changes once the LS has involuted (a phenomenon not found in lichen planus that affects the matrix) may further support the theory of an associated inflammatory trigger that can produce disturbance of nail matrix kinetics. A similar possible mechanism of a viral infection triggering a stress response on the nail matrix has been reported with onychomadesis following viral infections [6].

The authors believe that the relative rarity of both isolated onychodystrophy and LS and the rapid resolution of both nail and skin changes in our patients would support the theory of an environmental or infectious trigger.

Acknowledgements

References

2 Karp DL, Cohen BA. Onychodystrophy in lichen striatus. Pediatr Dermatol 1993; 10: 359-61.

3 Tosti A, Peluso AM, Misciali C, Cameli N. Nail lichen striatus: clinical features and long-term follow-up of five patients. J Am Acad Dermatol 1997; 36: 908-13.

4 Patrizi A, Neri I, Fiorentini C, et al. Simultaneous occurrences of lichen striatus in siblings. Paediatr Dermatol 1997; 14: 293-5.

5 Taieb A, el Youbi A, Grosshans E, Maleville J. Lichen striatus: a Blaschko linear acquired inflammatory skin eruption. J Am Acad Dermatol 1991; 25: 637-42.

6 Bernier V, Labreze C, Bury F, Taieb A. Nail matrix arrest in the course of hand, foot and mouth disease. Eur J Pediatr 2001; 160: 649-51.