Case 16 A 33-year-old Thai male from Bangkok Chief complaint: Skin rashes at both upper extremities for 2 years Present illness: Itchy erythematous patches first appeared at dorsal side of both hands and then spread proximally to both forearms and arms. He also noticed similar lesion at anterior part of trunk and posterior part of neck. He was treated with laser from other hospital without any improvement. Personal history: No underlying disease Family history: No family history of similar skin lesion Physical examination: Ill-defined brown-gray patchs with erythematous hue symmetrically distributed at dorsal side of both hands and posterior part of neck. There are linear streak of brown-gray patch with erythematous hue at both arms and forearms. Multiple discrete and confluent ill-defined dark brown-gray macules and patches at anterior part of abdomen. No lesion at oral mucosa and nail.

Fig 16.1 Fig 16.2

Fig 16.3 Fig 16.4

Fig 16.5 Fig 16.6

Positive findings: AST 205 mg/dl, ALT 342 mg/dl, Anti HCV-positive Histopathology: (S08-8882 Right forearm, S08-9530 Left arm)

- Superficial lichenoid infiltrate of lymphocytes admixed with melanophages in the papillary dermis, obscuring the dermoepidermal junction

- Orthokeratosis, focal hypergranulosis, focal epidermal atrophy and vacuolar alteration in the epidermis

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Diagnosis: Lichen planus pigmentosus Presenter Poonkiat Suchonwanit Vasanop Vachiramon Consultant Natta Rajatanavin Discussion: Lichen planus pigmentosus has been described as a condition of unknown etiology which clinically differs from the classical lichen planus by exhibiting dark brown macules and/or papules, mottled or reticulated hyperpigmentation and a longer clinical course without scalp, nail, or mucosal involvement. It is most common on sun-exposed areas such as the face, neck, and flexural folds including the axilla, inguinal, and submammary regions.1 Some authors observed a striking predominance of lesions in an intertriginous location, with most of them in the axillae, thus they proposed the designation lichen planus pigmentosus inversus.2 Less common presentations include involvement of non sun-exposed areas such as thigh,3 zosteriform pattern on the trunk4 and linear unilateral lesion on the extremity.5 Histopathologic findings consist of atrophic epidermis with vacuolar alteration of the basal cell layer, and a scarse lymphohistiocytic or lichenoid infiltrate in the dermis with incontinence of pigment and the presence of melanophages.1 The cause of Lichen planus pigmentosus is unknown. As in lichen planus, type IV hypersensitivity reactions seem to play an important role in its pathogenesis. Lichen planus pigmentosus frequently appears in patients on medications.6

The association between hepatitis C virus and lichen planus has been extensively reviewed and it is significantly associated in Southern Europe and Japan but not in Northern Europe.7 In Thailand, the prevalence of HCV infection among patients with oral lichen planus is 8.33%.8 However, there is no previous report association between hepatitis C virus infection and lichen planus pigmentosus.

Considerations in the differential diagnosis include ashy dermatosis, contact and occupational dermatosis with hyperpigmentation, and drug-related dermatoses. Most of these can be differentiated by occupation, history of drug intake, or clinical findings, but Ashy dermatosis is the most important and difficult in the differential diagnosis. Some authors believe that it is a different entity1 while the others believe that it is a continuous spectrum of the same disease process.9,10

No specific treatment is available for lichen planus pigmentosus. Multiple drugs have been used, including topical steroids and keratolytics.6 Some cases has responded to a 10% aqueous solution of DMSO applied topically. Other drugs used with inconsistent results are griseofulvin, prednisone, etretinate, and chloroquine.4

Disapperance of lichen planus after interferon alpha treatment for HCV infection has been reported.11 However, no large studies have evaluated the impact of IFN on HCV-associated LP or whether the presence of LP predicts sustained virologic response. Numerous case reports have documented the development or worsening of LP during IFN therapy for HCV infection, including cases with sustained virologic response.12

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Reference 1. Vega ME, Waxtein L, Arenas R, Hojyo T, Dominguez-Soto L. Ashy

dermatosis versus lichen planus pigmentosus: a controversial matter. Int J Dermatol 1992; 31(2): 87-8.

1. Pock L, Jelinkova L, Drlik L, et al. Lichen planus pigmentosus-inversus. J Eur Acad Dermatol Venereol 2001; 15(5): 452-4.

2. Kim KJ, Bae GY, Choi JH, et al. A case of localized lichen planus pigmentosus on the thigh. J Dermatol 2002; 29(4): 242-3.

3. Cho S, Whang KK. Lichen planus pigmentosus presenting in zosteriformpattern. J Dermatol 1997; 24(3): 193-7.

4. Hong S, Shin JH, Kang HY. Two cases of lichen planus pigmentosus presenting with a linear pattern. J Korean Med Sci 2004;19(1):152-4.

5. Dominguez-Soto L, Hojyo-Tomoka T, Vega Mamije E, Arenas R, Cortes-Franco R. Pigmentary problems in the tropics. Dermatologic clinics 1994; 12(4): 777-84.

6. Carrozzo M, Pellicano R. Lichen planus and hepatitis C virus infection: an updated critical review. Minerva Gastroenterol Dietol 2008; 54(1): 65-74.

7. Klanrit P, Thongprasom K, Rojanawatsirivej S, Theamboonlers A, Poovorawan Y. Hepatitis C virus infection in Thai patients with oral lichen planus. Oral Dis 2003; 9(6): 292-7.

8. Kark EC, Litt JZ. Ashy dermatosis. A variant of lichen planus? Cutis 1980; 25(6): 631- 3.

9. Berger RS, Hayes TJ, Dixon SL. Erythema dyschromicum perstan and lichen planus: are they related? J Am Acad Dermatol 1989; 21(2 Pt 2): 438-42.

10. Doutre MS, Beylot C, Couzigou P, et al. Lichen planus and virus C hepatitis: disappearance of the lichen under interferon alfa therapy. Dermatology 1992; 184(3): 229.

11. Berk DR, Mallory SB, Keeffe EB, Ahmed A. Dermatologic disorders associated with chronic hepatitis C: effect of interferon therapy. Clin Gastroenterol Hepatol 2007; 5(2): 142-51.

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