Pigment International

CASE REPORT
Year
: 2016  |  Volume : 3  |  Issue : 1  |  Page : 43--45

Lichen planus: Zosteriform or along the lines of Blaschko?


RahulKrishna S Kota, Nidhi B Jivani, Pragya Ashok Nair 
 Department of Dermatology and Venereology, Pramukhswami Medical College, Karamsad, Anand, Gujarat, India

Correspondence Address:
Dr. Pragya Ashok Nair
Department of Dermatology and Venereology, Pramukhswami Medical College, Karamsad, Anand - 388 325, Gujarat
India

Abstract

Lichen planus (LP) is relatively common papulosquamous condition characterized by purple, polygonal, pruritic, papules of unknown etiology affecting skin, mucous membranes, and the nails. It can range from the generalized to much localized form. Zosteriform LP is an uncommon variant with dermatomal or zonal distribution and may arise either de novo, at sites of trauma (koebnerization) or as Wolf's isotopic response at the site of healed zoster. Linear distribution of the disease has been described in less than 1% of patients and needs to be differentiated from other linear dermatoses. Treatment includes topical corticosteroids and systemic antihistamines. A 30-year-old male diagnosed with LP involving C7 (Cervical) dermatome over left side of the body in a zosteriform pattern is presented here.



How to cite this article:
Kota RS, Jivani NB, Nair PA. Lichen planus: Zosteriform or along the lines of Blaschko?.Pigment Int 2016;3:43-45


How to cite this URL:
Kota RS, Jivani NB, Nair PA. Lichen planus: Zosteriform or along the lines of Blaschko?. Pigment Int [serial online] 2016 [cited 2022 Aug 16 ];3:43-45
Available from: https://www.pigmentinternational.com/text.asp?2016/3/1/43/184262


Full Text

 Introduction



Lichen planus (LP) is a common, chronic eruption, characterized by flat-topped, purple colored papules which are pruritic.[1] It usually involves flexural parts of the extremities, mucous membranes, nails, and scalp. Its etiology is not known, but T cell-mediated disorder expressing antigens which are altered on the surface of basal keratinocytes modified by viruses or drugs are believed to be the cause.[2] Many morphological variants of LP have been described, of which linear and zosteriform LP are rare and the unilateral LP seems to be rarer.[2]

Linear LP, first described in 1854, is uncommon and accounts for 0.24–0.62% of all cases.[3] It can be linear as a result of Koebner's phenomenon and appear as a band of lesions in a dermatomal or Blaschkoid distribution.[4] Zosteriform LP is an uncommon variant with dermatomal or zonal distribution and may arise either de novo, at sites of trauma (koebnerization) or as Wolf's isotopic response at the site of healed zoster. Cases of true zosteriform LP-like eruptions are extremely rare and may be explained as a Koebner phenomenon induced by a preceding herpes zoster infection.[5] Topical steroids are the mainstay of treatment. Here, we present a case of a 30-year-old male with LP involving C7 (Cervical) dermatome over left side of body.

 Case Report



A 30-year-old male patient presented to skin Outpatient Department with asymptomatic lesions over left upper extremity and trunk since 4 months. History of papules which healed with hyperpigmentation was elicited. No history of herpes zoster or any other dermatoses at the site of the lesions could be elicited. There was no history of trauma, fever, any infective focus, or dental procedure in the past and no similar complaints were reported in the past or family. On examination, multiple violaceous to hyperpigmented papules were present over left elbow [Figure 1]a and index finger [Figure 1]b. Multiple hyperpigmented macules and patches were present over left side of back, arm [Figure 2]a, forearm [Figure 2]b, and index finger appearing to involve C7 dermatome. Nails, scalp, genital, and oral mucosa were normal. Systemic examination was unremarkable with no lymphadenopathy.{Figure 1}{Figure 2}

Histopathology revealed compact orthokeratosis, mild acanthosis, and vacuolar degeneration of basal layer. Dermoepidermal junction was obscured with focal necrosis of basal keratinocytes leading to pigment incontinence. Upper dermis showed an intense band-like lymphoplasmocytic infiltrate with occasional eosinophils [Figure 3]. These changes were suggestive of LP. Patient was advised to apply topical steroids twice a day and was called for follow-up after 1 month. Papules flattened with no appreciable improvement in hyperpigmented patches.{Figure 3}

 Discussion



LP is a common papulosquamous condition which can range from generalized to much localized form. Less commonly, it may have a linear arrangement. Blaschkoid LP is seen in only 0.5% of patients along blaschkoid lines which are invisible lines in the skin that are to trace the migration of embryonic cells and do not correspond to nervous, vascular, or lymphatic structures.[6] These lines represent a form of “mosaicism,” where two or more genetically distinct cell populations are present in an individual derived from a single zygote while dermatome is an area of skin supplied by a spinal cutaneous nerve.[7]

Like LP, certain acquired and congenital diseases such as lichen striatus, inflammatory linear verrucous epidermal nevus, nevus unius lateris, drug eruptions, dermatitis herpetiformis, segmental neurofibromatosis, or scleroderma may display a zosteriform pattern and manifest in linear or zosteriform distribution following the embryonic Blaschko's lines. The linear-zosteriform arrangement of these skin disorders may be explained as a Koebner phenomenon or as a cutaneous reaction possibly triggered by still unrecognized agents.[8]

Blaschko's lines are V-shaped over the upper spine, S-shaped on the abdomen, and inverted U-shape from the breast area onto the upper arm, while over the front and the back of the lower extremities these lines are perpendicular. These have been confused with dermatomes as in both the distribution patterns are characterized by a striking demarcation of cutaneous lesions at the midline. However, on close comparison, the two do not seem to be related, though on the upper extremities there is a resemblance to the anatomical location of the motor nerves.[9]

The lesions in zosteriform or linear LP actually follow the lines of Blaschko rather than an actual dermatome.[8]

It is very difficult to explain the occurrence of an acquired disorder such as LP along the Blaschko's lines, which are normally followed by the inherited/genetic disorders and that too limited to one half of the body. A genetic predisposition to LP and exposure to an appropriate environmental or endogenous trigger leads to its development along those lines.

Such a distribution of lesions has provoked many authors to suggest a theory of neural origin to the linear/zosteriform LP. Hence, it remains unexplored if there are two separate forms of unilateral, de novo LP: One type arising in the lines of Blaschko (Blaschkoid LP) and the other arising within one or more dermatomes (dermatomal LP).[10] Some authors believe that true zosteriform LP only exists in cases who have developed lesions on the sites of healed herpes zoster.[11]

There is a definite distinction between linear and zosteriform type of LP, to which there has not been strict adherence. In the former condition, the papular lesions appear as narrow lines about 1 or 2 cm wide, which may follow the course of a nerve, of a vein or a lymphatic vessel or one of Voigt's lines. In the latter, the lesions form a band several centimeters wide that follows the course of a peripheral cutaneous nerve and its branches or appears over areas of radicular nerve distribution, i.e., following the dermatomal distribution.[12] There is a controversy about the use of terms such as zosteriform/dermatomal LP and Blaschkoid LP.[7]

The question is to which of these categories our case should be assigned. In our patient, a unilateral, zosteriform, papular eruption was seen along the C7 dermatome but without any history of previous varicella zoster virus (VZV) infection, which can be explained either by a subclinical VZV infection or by a VZV reactivation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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