Indian Journal of Dermatology
ORIGINAL ARTICLE
Year
: 2019  |  Volume : 64  |  Issue : 5  |  Page : 341--345

Role of dermoscopy in the diagnosis of hypertrophic lichen planus and prurigo nodularis


Bangaru Hanumaiah, Joice Maria Joseph 
 Department of Skin and VD, Mysore Medical College and Research Institute, Mysore, Karnataka, India

Correspondence Address:
Joice Maria Joseph
Department of Skin and VD, Mysore Medical College and Research Institute, Mysore, Karnataka
India

Abstract

Background: A dermoscope is an office tool used in the diagnosis of various disorders. At present, studies on hypertrophic lichen planus (HLP) and prurigo nodularis (PN) are limited. Aims and Objectives: The aim of this study was to compare the dermoscopic features of HLP and PN and to determine the role of dermoscopy in the differential diagnosis of both the conditions. Materials and Methods: A cross-sectional study was undertaken. After clinical assessment and relevant investigations, dermoscopy was performed using DermLite DL3 dermoscope (×10) followed by histopathology. Dermoscopic findings in cases of HLP and PN were evaluated. Results: Thirty patients each with HLP and PN were included in the study. On dermoscopy, peripheral striations were the most common findings in both the conditions. Statistically significant features on intergroup comparison included blue–gray globules (P <0.001), comedo-like openings (P <0.001), and follicular plugging (P <0.001) in HLP and pearly white areas with white starburst pattern (P =0.028), red dots and globules (P <0.001), glomerular vessels (P =0.003), crusting (P =0.002), and erosions (P <0.001) in PN. Conclusion: Dermoscopy is useful in differentiating HLP and PN. Blue-gray globules, comedo-like openings, and follicular plugging were specific for HLP. Pearly white areas with white starburst pattern and red dots and globules were the specific findings in PN.



How to cite this article:
Hanumaiah B, Joseph JM. Role of dermoscopy in the diagnosis of hypertrophic lichen planus and prurigo nodularis.Indian J Dermatol 2019;64:341-345


How to cite this URL:
Hanumaiah B, Joseph JM. Role of dermoscopy in the diagnosis of hypertrophic lichen planus and prurigo nodularis. Indian J Dermatol [serial online] 2019 [cited 2019 Dec 12 ];64:341-345
Available from: http://www.e-ijd.org/text.asp?2019/64/5/341/265933


Full Text



 Introduction



A dermoscope (dermatoscope) is a noninvasive, diagnostic tool which visualizes subtle clinical patterns of skin lesions and subsurface skin structures not normally visible to the unaided eye. It has also been called a skin surface microscope, epiluminescence microscope, or episcope. Some dermoscopic patterns are observed consistently with certain diseases and these then could be used for their diagnosis.[1]

Hypertrophic lichen planus (HLP) also known as LP verrucosus usually occurs on the extremities, especially the shins and interphalangeal joints, and tends to be the most pruritic variant. Lesions are thickened and elevated, purplish or reddish-brown in color, and hyperkeratotic and may show accentuated and elevated follicular induration and chalk-like scale [Figure 1]. This variant usually heals with scar formation and hyper- or hypopigmentation.[2]{Figure 1}

They must be distinguished from lichen simplex chronicus and lichen amyloidosus (papular). Multiple cutaneous horns, keratoacanthoma, and malignant transformation arising in hypertrophic LP have been reported.[3]

Prurigo nodularis (PN) is a chronic inflammatory dermatosis which usually occurs in individuals between 20 and 60 years old. In 1879, Hardaway described for the first time PN as multiple tumors of the skin accompanied by itching.[4] Hyde used the term PN for the first time in 1909.[5] PN is characterized clinically by the presence of numerous symmetrically distributed hyperkeratotic or eroded nodules [Figure 2].[6]{Figure 2}

The diagnosis of PN is mainly clinical, based on its distinctive features. However, the clinical differentiation from other nodular dermatoses, particularly HLP, nodular scabies, multiple keratoacanthomas, and reactive perforating collagenosis, may sometimes be a diagnostic challenge; in such cases, histopathologic examination is needed to reach a definitive diagnosis.[7]

However, in some cases, even a biopsy cannot provide the accurate information necessary for differentiation. Therefore, we conducted a cross-sectional study to evaluate the importance of handheld dermoscopy in distinguishing HLP from PN.

 Materials and Methods



The study was conducted at the Department of Dermatology, Mysore Medical College and Research Institute, Mysore, from March 2017 to November 2017. This was a cross-sectional study approved by the institutional ethics committee before patient enrollment. Thirty patients each with clinical signs and symptoms of HLP and PN confirmed with histopathology were included in the study.

Exclusion criteria were invasive or noninvasive procedure over the lesion in the past 6 weeks, use of steroids in the past 6 weeks, pregnant and lactating women, and keloidal tendency.

Patients' demographic data were documented and the single most recently developed lesion was examined dermoscopically and histopathologically. Dermoscopy preceded histology. No treatment was allowed during this time and the patients received appropriate treatment after the histological report.

Dermoscopic images were recorded from each patient using a handheld dermoscope DermLite DL3 (3Gen, Dana Point, CA, USA) equipped with a camera (Coolpix Nikon; ×20). All pictures were evaluated by two of the authors for the presence of specific morphological features. Variables included in the dermoscopic evaluation were peripheral striations, blue-gray globules, comedo-like openings, pearly white areas, red dots and globules, glomerular vessels, brownish black globules, yellowish structures, follicular plugging, crusting, erosions, and scales. Selection of dermoscopic criteria for the evaluation process was based on the available literature data.[7],[8],[9]

Histopathological examination was also performed by two pathologists who were blinded to the dermoscopic diagnosis.

Epidermal hyperplasia, acanthosis, hypergranulosis, compact and lamellated hyperkeratosis centered on follicular infundibula and acrosyringia, and basal cell damage confining to the tips of rete ridges were the criteria for the histopathological diagnosis of HLP.[10]

The characteristic histopathology of PN included the presence of thick, compact orthohyperkeratosis, irregular epidermal hyperplasia or pseudoepitheliomatous hyperplasia, focal parakeratosis, and hypergranulosis, papillary dermis showing fibrosis with vertically arranged collagen fibers and increased number of fibroblasts and capillaries.[11]

Statistical analysis was performed using Chi-square test for evaluating the statistical significance between two groups. P <0.05 was considered as statistically significant. All the analyses were performed using SPSS software (Statistical Package for the Social Sciences version 16; Chicago, USA)

 Results



During the 9 months of the study, 96 patients were screened for eligibility of the study participation. Of these, 36 patients were excluded because of concurrent treatment with steroids, lack of definite histopathological features, and withdrawal from the study. Thirty patients each of HLP and PN were finally included.

Of 30 HLP cases, 21 patients were male and 9 patients were female. The mean age of the study group was 43 year (range 10–76 years). Histopathology of HLP showed hyperkeratosis, acanthosis, hypergranulosis, and basal cell damage confined to the tips of rete ridges [Figure 3]a. The dermoscopic findings are summarized in [Table 1]. The most common dermoscopic finding observed was peripheral striations (in 29 patients; 96.7%) which appeared as radially arranged whitish lines with pearly white areas [Figure 4] and [Figure 5]. Other most frequent dermoscopic findings were comedo-like openings (26 cases; 86.7%), yellowish structures (16 cases; 53.3%), follicular plugging (16 cases; 53.3%), and blue-gray globules (12 cases; 40%).{Figure 3}{Table 1}{Figure 4}{Figure 5}

Other less common dermoscopic features included scales (11 cases; 36.7%), brownish-black globules (9 cases; 30%), red dots and globules (5 cases; 16.7%), and crusting, erosions, and glomerular vessels (2 cases each; 6.7%).

Of the 30 PN cases, 22 patients were female and 8 patients were male with the mean age of 41.2 year ranging from 14 to 78 years. Histopathology of PN showed orthokeratosis and hyperkeratosis, irregular acanthosis, elongated rete ridges, and vertically arranged collagen fibers in the dermis [Figure 3]b. The most common dermoscopic findings observed were peripheral striations (25 patients; 83.3%) and pearly white areas with white starburst pattern (24 patients; 80%) [Figure 6]. Frequencies of each dermoscopic pattern in HLP and PN are shown in [Table 1].{Figure 6}

Through Chi-square analysis, blue-gray globules (P <0.001), comedo-like openings (P <0.001), and follicular plugging (P <0.001) were found to be more specific for the diagnosis of HLP than PN. Furthermore, it was statistically found that pearly white areas with white starburst pattern (P =0.028), red dots and globules (P <0.001), glomerular vessels (P =0.003), crusting (P =0.002), and erosions (P <0.001) [Figure 6] and [Figure 7] are more specific for the diagnosis of PN.{Figure 7}

 Discussion



LP is a common papulosquamous disorder involving the skin, nails, and mucosae.[3] HLP is a subacute or chronic variant of LP characterized by hypertrophic or warty lesions, most commonly found on the pretibial area of the lower limbs. HLP on the legs tends to persist and has a propensity for malignant transformation even in young patients.[12],[13],[14]

PN is a chronic, intensely pruritic nodular condition usually found on the lower extremities, though it can occur anywhere on the body.[15] The etiology of the disease is still unclear. Three types have been described in the literature: (a) atopic, (b) nonatopic, and (c) human immunodeficiency virus associated.[16]

Most prominent dermoscopic findings in HLP and PN in our study were peripheral striations with pearly white areas. In HLP, it was arranged peripherally only in some areas, while in PN, it consisted of central white areas with peripheral extensions involving the whole lesion giving rise to “starburst appearance.” Similar observations were made by Errichetti et al.[7] and Ankad and Beergouder.[8] Histopathologically peripheral striations with pearly white areas correspond to compact orthokeratosis above zones of wedge-shaped hypergranulosis, acanthosis, and dermal fibrosis.[8],[9]

In our study, comedo-like openings were found to be significant in HLP. It was described as openings filled with yellow keratinous plugs by Vázquez-López et al.[17] It corresponds to dilatation, plugging, and hypergranulosis of the infundibula and is suggestive of transepithelial elimination.[8],[9]

Blue-gray globules were present only in HLP (40% of cases) and found to be very specific for the diagnosis. The blue-gray globules correlate with the presence of pigment-laden melanophages in the dermis. It is suggestive of regressing lesions.[18] Gray-blue globules can be found in lichen planopilaris where it appears in a “targetoid” pattern.[19],[20] In this study, blue-gray globules in HLP were arranged in diffuse structureless pattern interspersed in pearly white areas, indicating the presence of melanin incontinence in perifollicular and interfollicular areas. In our study, blue-gray globules were not demonstrated in PN, suggesting the absence of pigmentary incontinence in PN. This was similar to the observations made in previous studies.[8],[9]

Yellow structures were present in 53.3% of HLP cases. Yellow structures were not demonstrated in PN. It represents spongiosis and vacuolar degeneration of the basal layer.[8] Brownish-black globules in dermoscopy histopathologically represent melanocytes in the epidermis. In HLP, brownish-black globules were present in a diffuse pattern which was similar to the observation made by Ankad and Beergouder.[8] Brownish-black dots were not found statistically significant in PN.

Red dots were clusters of dotted vessels (diameter 0.01–0.02 mm), similar to that of a pinhead.[18] Red dots corresponded to dilated capillaries in histopathology.[8] The presence of linear or dotted vessels located around the whitish striae was typically seen during the active phase of inflammation in LP.[18] In our study, red dots were observed in both HLP and PN. However, it was found to be significantly higher in PN.

Red globules were larger than the red dots. Glomerular vessels were tightly coiled, tortuous vessels shaped like the glomerulus of the kidney, larger than dotted vessels. These corresponded to enlarged blood vessels as well as focal hemorrhage in dermis.[8],[21] These were prominent in PN and were not evidently seen in HLP in this study. Most commonly, glomerular vessels were associated with squamous cell carcinomas, in which the glomerular vessels were principally distributed focally in clusters and at the periphery of the lesion together with hyperkeratosis.[22],[23] Therefore, the presence of glomerular vessels on dermoscopy could be an indication of malignant change in HLP and PN. In our study, glomerular vessels were found to be significantly higher in PN. Similar findings were observed by Errichetti et al.[7]

Dermoscopy is a reliable, simple, easy-to-use diagnostic technique that serves as a link between macroscopic skin lesions and microscopic histopathological features. HLP and PN demonstrate specific dermoscopic patterns that correlate with histopathologic findings. Peripheral striations were seen as the most common findings in both the conditions. Blue-gray globules, comedo-like openings, and follicular plugging were specific to HLP. Pearly white areas with white starburst pattern, red dots and globules, glomerular vessels, crusting, and erosions were more specific for the diagnosis of PN.

 Conclusion



In comparison with the previous studies, the unique aspects of our study are the larger sample size and determination of specificity of each dermoscopic finding in comparing HLP and PN. In conclusion, this study shows that dermoscopy is a valuable noninvasive tool for differentiating HLP and PN and it can reduce the frequency of unnecessary skin biopsies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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