Linear lichen planus along the lines of Blaschko

Samia Mrabat, Hanane Baybay, Zakia Douhi, Imane Couissi, Sara Elloudi, Fatima Zahra Mernissi

Department of Dermatology, University Hospital Hassan II, Fes, Morocco

Corresponding author: Samia Mrabat, MD

Submission: 02.12.2020; Acceptance: 09.03.2021

DOI: 10.7241/ourd.2021e.31

Cite this article: Mrabat S, Baybay H, Douhi Z, Couissi I, Elloudi S, Mernissi FZ. Linear lichen planus along the lines of Blaschko. Our Dermatol Online. 2021;12(e):e31.

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Lichen planus (LP) is an inflammatory dermatosis that presents with pruritic papules, with LP lesions along the lines of Blaschko representing a rare variant. There are several terms for this entity, including linear LP, Blaschko linear LP, and Blaschkoid LP [1]. LP in a Blaschkoid distribution is uncommon variant, estimated to affect 0.24% to 0.62% of all LP patients [2]. The term of linear LP is used to describe lesions along the lines of Blaschko, demonstrating a characteristic S shape on the abdomen, V shape near the posterior midline, a linear pattern on the lower trunk and limbs, and whorls on the scalp and abdomen [1]. Its linear arrangement outside of Koebner’s phenomenon would be due to genetic mosaicism responsible for the presence of a keratinocyte clone capable of reacting under the effect of immunogenic, exogenous or infectious factors. We describe a case of lichen planus with Blaschkoid presentation.

An otherwise healthy 48-year-woman presented with a 6- month history of pruritic erythematous lesions on her lower limb. Clinical examination found linear, non-scaly ; violaceous-to-erythematous, macules and patches in the right lower limb extending from the thigh to the knee (Fig. 1).

Figure 1: Clinical picture showing linear macules and patches extending from the tigh to the knee.

Dermoscopy showed white lines with a reticular arrangement corresponding to Wickham striae within a pink background as well as peripheral dotted vessels (Fig. 2). Systemic examination was normal. There were no lesions on the mucosas, hair and nails. The clinical diagnosis was Blaschkoid lichen planus and the patient was treated with very potent dermocorticoids.

Figure 2: Dermoscopic picture showing white fine lines corresponding to Wickham striae (blue arrows),with dotted vessels (blue asterisk).

Consent

The examination of the patient was conducted according to the principles of the Declaration of Helsinki.

The authors certify that they have obtained all appropriate patient consent forms, in which the patients gave their consent for images and other clinical information to be included in the journal. The patients understand that their names and initials will not be published and due effort will be made to conceal their identity, but that anonymity cannot be guaranteed.

REFERENCES

1. Criscito MC, Brinster NK, Skopicki DL, Seidenberg R, Cohen JM. Blaschkoid lichen planus:Throwing a “curve“in the nomenclature of linear lichen planus. JAAD Case Rep. 2020;6:237-9.

2. Gorouhi F, Davari P, Fazel N. Cutaneous and mucosal lichen planus:a comprehensive review of clinical subtypes, risk factors, diagnosis, and prognosis. Scientific World J. 2014;10:1-22.

Notes

Source of Support: Nil,

Conflict of Interest: None.