|LETTER TO EDITOR
|Year : 2021 | Volume
| Issue : 3 | Page : 186-187
Unilateral lichen planus pigmentosus inversus: a rare presentation
Divya Kamat, Muthu Sendhil Kumaran
Department of Dermatology, Venereology and Leprology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
|Date of Submission||27-Aug-2020|
|Date of Decision||27-Jan-2021|
|Date of Acceptance||16-Apr-2021|
|Date of Web Publication||24-Nov-2021|
Dr. Muthu Sendhil Kumaran
Department of Dermatology, Venereology and Leprology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012
Source of Support: None, Conflict of Interest: None
Keywords: Flexural, inversus, lichen planus pigmentsosus
|How to cite this article:|
Kamat D, Sendhil Kumaran M. Unilateral lichen planus pigmentosus inversus: a rare presentation. Pigment Int 2021;8:186-7
Lichen planus pigmentsosus (LPP) inversus is an unusual variant of LPP with fewer cases of unilateral distribution reported worldwide. In a retrospective cohort from our center, flexural lesions were present in only 2 of 76 (2.6%) cases. We report a rare case of unilateral LPP inversus that like other variants had poor response to treatment.
A 45-year-old female presented with 1-year duration of multiple, slightly pruritic, well-defined slate grey macules on the left axilla [Figure 1]. There were no prior inflammatory lesions. The grey macules coalesced together with few smaller discrete macules in the periphery and lacked surrounding erythema. Dermatoscopy showed diffuse grey brown pigmentation with few brownish granular dots [Figure 2]a. Other flexures, nails, mucosa, and scalp were spared. Histopathology demonstrated a lichenoid reaction pattern with prominent pigment incontinence [Figure 2]b. The diagnosis of LPP inversus was made and patient started on topical 0.05% tacrolimus cream daily at night. Due to unsatisfactory response after 4 months of treatment, patient was advised to discontinue the cream.
|Figure 2 (a) Dermoscopy showing diffuse grey brown pigmentation with few brownish dots (circle) and globules (square) with sparing of skin creases (triangles; DL3N, 10×). (b) Lichenoid reaction pattern with prominent pigment incontinence (Hematoxylin and Eosin stain, 40×)|
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Inverse LPP initially described by Pock et al. in 2001 is a rare variant of LPP. In their report of LPP inversus, upto 10% of cases had lesions outside the flexural areas. Humid environment, sweating, ill-fitting garments leading to koebnerization have all been postulated as triggering factors. Some authors have also reported the simultaneous presence of LP and LPP.
LPP inversus presents with slate grey to brown macules commonly located in the axillae and groin. Other flexures such as neck, anticubital fossae, auricular sulcus, and infra-mammary areas can also be involved. In most cases, lesions are bilaterally symmetrical with only few reports of unilateral LPP. Concurrent presence of atypical variants such as linear and flexural LPP has also been reported. The usual differential diagnoses include ashy dermatosis, acanthosis nigricans, fixed drug eruptions, erythrasma, and post inflammatory hyperpigmentation. Dermoscopic features described in LPP include brown to bluish dots, globules, and blotches that vary with the severity of pigmentation. These features are also common to Riehl’s melanosis, pigmented contact dermatitis, and ashy dermatosis. The histopathology findings are similar to that found in LP like band-like lichenoid pattern of inflammatory infiltrate composed of lymphocytes and prominent pigment incontinence and melanophages in the upper dermis. Few differences compared to LP include less prominent hypergranulosis and variable amount of inflammatory infiltrate.
Other atypical variants of LPP include linear, zosteriform, and follicular. The phenomenon of koebnerization has also been described in LPP.The overall response to treatment in all variants of LPP has been poor. Topical steroids and topical tacrolimus have been tried in earlier reported cases. There have been few reports of spontaneous resolution over few weeks to months.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]