Dermoscopic Features of Lichenoid Pseudovesicular Papular Eruption of the Nose (LiPEN): A Rare Entity.

Dear Editor, Lichenoid pseudovesicular papular eruption of the nose (LiPEN) is a distinct entity that affects young-middle-aged people and sometimes is photo aggravated. It is a diagnosis of exclusion of papules on the face that may be the presenting features of many dermatological conditions. Here, we are presenting a case series of 6 cases of LiPEN, which were diagnosed clinically and histopathologically. We also described the dermoscopic features. A total of six patients of LiPEN attending the dermatology outdoor of our tertiary care center, Govt medical college, Kota (Rajasthan), were studied. The study duration was 18 months. All the subjects included in the study were females and their age ranged from 14 to 45 years. These women complained of skin to erythematous shiny raised lesions that presented over the nose predominantly, extending away from paranasal areas of the nose [Figures 1-4]. Three out of six patients were asymptomatic, while the other three complained of itching and burning sensation on sun exposure. A written informed consent was taken. A skin biopsy was taken with a standard 4 mm punch. General and systemic examinations and routine were done. Skin biopsies showed localized nodular [H and E stain, 4×, 10×, 40×] [Figure 5] to diffuse pan dermal nodular lymphocytic infiltrate with multifocal vacuolar basal layer degeneration. Dermoscopy (Dermlite 3 with 10× magnification) was done on all the patients. The common dermoscopic findings observed were erythematous to brown globules with irregular outlines dispersed at regular intervals. These are consistent with pseudovesicular appearance. The background was less erythematous with some vascularity and scaling in normal skin markings. [Table 1] The patient was advised to use sunscreen all over the face and tacrolimus 0.03% ointment on the LiPEN lesions.Figure 1: Multiple grouped shiny erythematous papules present over the nose and adjoining areas (a), On dermoscopy well to ill-defined globules (blue arrow) and star-shaped (purple arrow) erythematous areas surrounded by grey areas (green arrow) in reticular pattern (Dermlite 3, 10×) (b) (before treatment), Reduction in the reddish-brown globules upon treatment (after 2 months of treatment) (c)Figure 2: Grouped erythematous lesions on the nose and adjoining area (a), multiple discrete flat-topped hypopigmented papules present on extensors of both arm and forearm, back, suggesting lichen nitidus (b), On dermoscopy star-shaped (purple arrow) erythematous areas surrounded by grey (green arrow) and slight erythema in reticular and net-like pattern (Dermlite 3, 10×) (c), on dermoscopy of forearm, oval to round hypopigmented areas with central depressed areas in some lesions over skin markings (d)Figure 3: Multiple grouped skin-colored to erythematous papules with interspersed hairy projections are present on the nose known as trichostasis spinulosa (a), on dermoscopy there are irregular and some star-shaped erythematous areas are present, along with black dots (black arrow) having hair projections over the nose (Dermlite 3, 10×) (b)Figure 4: Multiple grouped erythematous lesions of LiPEN are present over the noseFigure 5: Histopathology from nose, shows focal nodular lymphocytic infiltrate with multifocal vacuolar basal layer degeneration (green square- lymphocytic infiltrate; purple arrow- vacuolar basal layer degeneration) [H and E stain, 4× (a), 10× (b)]Table 1: Summary of our 6 casesLiPEN is a diagnosis of exclusion, as papular lesions may present in many other dermatoses. Differentiation of LiPEN should be done from various dermatoses as in Table 2. Micropapular variant of the polymorphous light eruption histopathologically includes lichenoid dermatitis resembling lichen nitidus, spongiotic dermatitis, and psoriasiform dermatitis.[1–6] Another entity that needs to be differentiated from Lipen is actinic lichen nitidus, actinic lichen nitidus. Classical lichen nitidus predominantly occurring on sun-exposed sites which may show koebnerization. There is a debate whether it is a variant of micropapular polymorphous light eruption described as a summertime actinic lichenoid eruption (SALE),[1,7] or an independent entity.[3] As actinic lichen nitidus shows focal lichenoid infiltrate with the admixture of histiocytes and giant cells on histology, there was some clinical and histopathological resemblance in our cases. It was possible to differentiate our cases from actinic lichen nitidus due to the absence of histiocytes and the presence of striking features of pseudovesicular nature. It is still a dilemma to fit LiPEN into a variant of actinic lichen nitidus or facial micropapular polymorphous light eruptions.Table 2: Differential diagnoses of LiPENDermoscopic examination in these cases helped in establishing the diagnosis and it also made differentiating this entity from other similar disorders relatively easy. In one case, lichen nitidus-like lesions showed shiny round to oval hypopigmented areas with a central dot-like brownish pigmentation on dermoscopy while the dermoscopic findings of erythematous to brownish areas compatible with pseudovesicular eruptions in zig zag or reticular patterns on the background of mild erythema, were a constant feature observed in all the patients. The etiopathogenesis of LiPEN is still not clear, but some factors may be considered. Two patients complained of photosensitive erythema and burning sensation, so sunlight seemed to play a role. Two patients gave a history of partial remission of lesions in winters. One patient had lichen nitidus-like lesions over both extensors of arms and forearms, and its pathophysiology can be correlated with actinic lichen planus. One case also showed trichostasis spinulosa over the nose and gave a history of lesions aggravating with acne. On histopathology, nodular lymphocytic infiltrates relate to the erythematous globules and star-shaped areas on dermoscopy. In contrast, the interspersed grey areas on dermoscopy correspond to the multifocal vacuolar basal layer degeneration in histopathology. Saurabh Singh et al described this entity earlier.[8] Herein, we made an attempt to identify, study and enumerate the dermoscopic findings of LiPEN. We also discussed the close clinical differentials in brief. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.