Dermatology: Practical and Conceptual Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 1 Dermoscopy of Actinic Lichen Planus in Skin of Color Awatef Kelati1, Asmae Rasso2, Soumia Chiheb1 1 Dermatology Department, University Hospital Cheikh khalifa, and the University Hospital Mohammed VI. Faculty of Medicine, Mohammed VI University of Health and sciences (UM6SS), Casablanca, Morocco 2 Dermatology Department, Provincial Hospital of Tantan, Tantan, Morocco Key words: Dermoscopy, Actinic lichen planus, skin of color, lichen, lichen planus pigmentosus Citation: Kelati A, Rasso A, Chiheb S. Dermoscopy of Actinic Lichen Planus in Skin of Color. Dermatol Pract Concept. 2024;14(2):e2024101. DOI: https://doi.org/10.5826/dpc.1402a101 Accepted: November 12, 2023; Published: April 2024 Copyright: ©2024 Kelati et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Kelati Awatef, Dermatology Department, University Hospital Cheikh khalifa, and the University Hospital Mohammed VI. Faculty of Medicine, Mohammed VI University of Health and sciences (UM6SS), Casablanca, Morocco. Email: akelati@ um6ss.ma Introduction: Actinic Lichen Planus (ALP) is a rare photosensitive variant of lichen planus. Four sub- types can be distinguished: pigmented, annular (AALP), plaque-like and dyschromic ALP. Methods: This is a retrospective; descriptive and analytical study investigating the dermoscopic pat- terns of different subtypes of ALP in skin of color. Results: Sixteen adult patients were included in this study; the majority of them were young females, while five patients with the pigmented subtype of ALP were more than 50 years old. This subtype was more prevalent in patients with phototype IV. AALP was described in men with a very dark phototype. In pigmented melasma-like ALP, dermoscopy showed an annular granular pattern, white reticular and circular Wickham striae (WS) with hypopigmentation lacking skin creases, dots inside circles and an eccentric pigmentation on circles. In ALP, annular, circular WS; and perifollicular white halos with follicular plugs were described. The black hole pattern with dotted vessels was seen in the dyschromic ALP. White-yellow-bluish WS were noticed in plaque-type ALP with circumferential radial lines at the periphery. Conclusions: This descriptive study of dermoscopic patterns of various subtypes of ALP in skin of color highlighted new dermoscopic descriptions that vary according to the clinical variant or the morphology; lesions distribution; and phototype. Also, many epidemiological differences were found between our results and the literature concerning the older age of onset in melasma-like pigmented ALP, and the male predominance in annular ALP. ABSTRACT 2 Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 Introduction Actinic Lichen Planus (ALP) is a rare photosensitive variant of lichen planus (LP); that is known to occur generally in chil- dren and young adults of Middle Eastern countries [1]. It was documented using different terms such as lichen planus tropi- cus , lichen planus subtropicus, summertime actinic lichenoid eruption [2], and lichen planus actinicus [1]. The etiology is still unknown; however, UV radiation appears to be the ma- jor incriminated factor, since it occurs primarily during spring and summer, and involves mainly exposed areas of the skin [3]. The hormonal factor was also suggested, especially in me- lasma-like pigmented forms which are frequent in women [4]. Lesions are usually asymptomatic and involve sun- exposed areas, like the face; especially the forehead, and the extensor surfaces of upper extremities, mainly the dorsum of the hands [5]. Clinically, four subtypes of ALP can be distinguished: pigmented ALP , annular actinic LP (AALP), plaque-like ALP; and dyschromic ALP [5,6]. Pigmented ALP manifests as hyperpigmented (gray, brown, or black) inflammatory macules and patches on sun exposed areas, sometimes giving a melasma-like pattern [4], that worsens after sun exposure. AALP manifests as ery- thematous brown plaques that are annular in configuration, with central atrophy in some cases [5,7]. In the plaque-like type, the lesions are elevated brown-gray plaques, with a depressed brownish center; and an erythematous elevated border [8]. Dyschromic ALP presents as pinhead-sized, whit- ish angular infiltrated papules that tend to coalesce, forming lesions of 5 to 6 mm in diameter, with a small horny plug in the center, it is generally described on the posterior part of the neck and the dorsum of the hands [4]. Dermoscopy of LP in the skin of color was not fully in- vestigated, Wickham striae (WS) are more difficult to see in dark phototype. Also, their clinical picture may differ due to variations in morphology and configuration, or clinical fea- tures modification depending on the site of involvement [9]. In addition, ALP has not been well described, and existing data of skin imaging in this rare variant of LP concerns only few observations of annular ALP, and pigmented ALP with lack of precisions of dermoscopy in the different variants [1,5,10]. Objectives The main aim of this study was to describe and analyze dermoscopic patterns of different variants of ALP in skin of color. Methods A retrospective double-center descriptive and analyti- cal study was performed in the Dermatology Depart- ment of the University Hospital Cheikh khalifa, and the University Hospital Mohammed VI of Casablanca in Morocco, over a period of 3 months, digital dermoscopic images of dark-skinned patients with ALP- were exam- ined and reviewed by two dermatologists experienced in Dermoscopy. Subjects Patients with different subtypes of ALP were enrolled in the study. The diagnosis was based on the morphology and the distribution over photo-exposed areas, with a histological confirmation. Data Analysis For each patient, epidemiological and clinical data were col- lected, including the age and the gender, as well as the photo- type, lesions location, morphology and distribution. Dermoscopic images of the representative lesions were taken using a manual dermoscope (HEINE DELTA 30, or Dermlite DL 4) attached to a smartphone or a digital cam- era, with or without polarized light and with or without immersion. Variables used in the dermoscopic evaluation were WS (presence or absence), type of WS (radial, reticulate, linear, circular, annular, arboriform, perifollicular and mixed), hypopigmentation lacking skin creases, perifollicular hy- popigmentation, pigmented structures (diffuse brown pigmentation, blue-gray and brown dots, eccentric pigmen- tation on circles), follicular plugs, blood vessels (presence or absence and their morphology), background color, particu- lar structures and patterns ( annular granular pattern, black hole pattern, pigmented dots arranged in parallel lines, cir- cumferential radial lines). The annular-granular pattern was considered as multi- ple, gray dots and globules around the pilo-sebaceous units [11]. The black hole pattern was considered as grayish-white annular and reticular WS at the periphery of the lesions, and clustered brown-gray dots on a light brown background in the center [12]. Data extraction was performed using Excel software (Microsoft). These data were then analyzed using IBM SPSS Statistics version 20 software (IBM), Descriptive statistics were expressed as means and percentages. All subjects were informed of the conditions related to the study and gave their informed consent. Results Sixteen patients were included in this study. The mean age was 39.6 +/- 12.8 years (13-55 years); and the majority of pa- tients (7, 43.8%) were young adults (less than 35 years old), while five (31.3%) subjects with pigmented melasma-like subtype had more than 50 years old. Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 3 There was a female predominance (75%); with a male-to-female sex ratio of 0,33. All of our patients had dark phototype (IV 10 (62.5%), V 5 (25%); and VI 2 (12.5%)). Pruritus was absent in most cases, except in the inflam- matory areas where an erythema was noted clinically and upon dermoscopy in three patients. The most predominant clinical subtype in this study was pigmented ALP in twelve patients (75%) with phototype IV, and a melasma-like pattern in most of them, while a pig- mented classic-like ALP pattern (papules and patches) was described in one patient. The melasma- like variant affected the full face in seven (63.6%) patients, the forehead in ten (90.9%) patients, the lower part of the face in eight (72.7 ) patients, the neck in five (45.4%) patients, and the hands in two patients (18.2%) (Figure 1). AALP was noticed in two male patients with a very dark phototype (V and VI), body areas involved were the forehead and the dorsal side of the hands (Figure 4). The dyschromic and plaque-like ALP were noticed in one patient each, with the forehead involvement for the plaque subtype, and the hands involvement in the dyschromic subtype. Hair involvement was described in seven cases (43.7%), with no associated mucous membrane or nail involvement. In melasma-like pigmented ALP, dermoscopy showed an annular granular pattern, dots inside circles, and eccentric pigmentation on circles in all the cases. Reticular pigmenta- tion in 90.9%; and hypopigmentation lacking skin creases surrounded by diffuse peppering was described in 81.8% of cases. Peri-follicular hypopigmentation was found in 45.5% of patients, white reticular and arborescent WS surrounded by pigmented areas and brown to gray dots were described in 18.2% of cases. In AALP and plaque-like ALP, annular and circular white WS surrounded by pigmented areas were described, in ad- dition to reticular pigmentation, follicular plugs, white halo around follicular openings; pigmented dots arranged in par- allel lines; and circumferential radial lines at the periphery of some annular plaques. Figure 1. Pigmented Actinic Lichen Planus. Hyperpigmented (gray brown) macules and patches on sun exposed areas in a melasma-like pattern, that worsen after sun exposure. 4 Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 ALP is a rare variant of this disease with a seasonal oc- currence, a predilection for dark-skinned females, an earlier age of onset; and a longer course [8]. In this study, we have found that this disease did not affect only children and young female adults as it was re- ported in the literature [5,6], it was also noticed in older patients; especially for the pigmented melasma-like subtype, this was also reported in a clinicopathological study of ALP and lichen planus pigmentosus, with a female to male ratio of 1.74, and a mean age of patients of 48.02±14.83 [13], however; this study did not describe and focus on the differ- ent subtypes of ALP, and also dermoscopy was not reported. The pigmented melasma-like subtype was the most pre- dominant in our study, unlike data reported in the litera- ture, that the most frequently presenting form is the AALP [6,14], this pigmented subtype was known to occur mostly in women [15], which joined our results. However, our pa- tients with AALP were men with a very dark phototype. White-yellow-bluish WS were noticed in one patient with a very dark phototype and annular plaques on the dorsum of the hands . The black hole pattern was described in the patient with dyschromic ALP of the hands, with dotted vessels on the white annular WS in a radial linear distribution (Figures 2-10) . Histological confirmation reveals findings similar to those of classic LP with degeneration of the basal layer of the epidermis; a band-like lymphocytic infiltrate of the dermis obscuring the dermo-epidermal junction, with pigmentary incontinence, and follicular involvement in some cases . Conclusions There are many variants of lichen planus, the morphology and distribution differ largely depending on its clinical and histological subtype [5]. Figure 2. Dermoscopy of pigmented melasma-like Actinic Lichen Planus. Annular granular pattern (green circle) with reticular pigmentation, white linear and reticular Wickham striae (C and D, blue arrow), sur- rounded by pigmented areas and dots. Dots inside circles (blue circle) and eccentric pigmentation on circles (blue rectangle) in some areas. Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 5 Figure 4: Annular Actinic Lichen Planus. Pigmented annular plaques on the forehead and the dorsum of the hands in two dark-skinned patients. Figure 3. Dermoscopy of pigmented melasma-like A Actinic Lichen Planus. Annular granular pattern with reticular pigmen- tation, hypopigmentation lacking skin creases (blue arrow), surrounded by brow-gray dots. Dots inside circles (blue circle) and an eccentric pigmentation on circles (blue rectangle), with an erythematous background (red star). 6 Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 Figure 5. Dermoscopy of Annular Actinic Lichen Planus of the forehead. Reticular Wickham striae (blue star), and white halo around follicular openings with follicular plugs (yellow arrow) on the periphery of the plaque and pigmented structure- less area at the center (red star). Figure 6. Dermoscopy of Annular Actinic Lichen Planus on the dorsum of the hands. Central depressed pigmented area with white halo at the center (green arrow). White- yellow-bluish Wickham striae (red arrow) with circumferential radial lines at the periphery of the plaques (blue star), and pigmented dots arranged in parallel lines (blue arrow). In various subtypes of LP, WS have been reported to be structured white areas that correlate with an increase in the granular cell layer in the epidermis, or a focal increase in the epidermal activity and irregular acanthosis leading to striae formation. Blood vessels were especially noticed -in fair phototype- around WS with a lack of dermal vessels in the striae area [9], due to epidermal proliferation that decreases their visualization [16]. However in pigmented forms of LP, especially macular lesions, and in very dark phototypes, WS can be difficult to see, can have various forms, or can be unapparent. Hypopigmentation lacking skin creases sur- rounded by pigmented dots and areas was a frequent finding in the pigmented melasma-like subtype in our study. Annular configuration of ALP was particularly reported [12,17], with a white-bluish coloration of WS [17], which was also noticed in our study in AALP and plaque-like ALP. Pigmented dots Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 7 Figure 7. Annular Actinic Lichen Planus (A) Before treatment: white halo around follicular openings (blue arrow); and Wickham striae (green arrow). (B) After treatment: disappear- ance of these dermoscopic signs, with persistence of pigmented structures (pigmented areas, and dots) (red arrow). Figure 8. Plaque-like Actinic Lichen Planus. (A) Confluent brown-gray plaques on the forehead with a depressed brownish center in some spots (8). (B) Dyschromic Actinic Lichen Planus. Pinhead-sized, whitish confluent papules, with a small horny plug in the center, on the dor- sum of the hands. arranged in parallel lines, and circumferential radial lines at the periphery of the lesions were new dermoscopic signs de- scribed in these patients. In the active stage of LP, many dermoscopic findings could be found, mainly WS surrounded by dotted or lineal vessels enhancing their visualization, and erythema. In dark skin, WS are the main structures described in active lesions with an absence of vascular structures [17], except for the dyschromic ALP, as we reported in our study, where we can find dotted vessels in a linear and a radial distribution on annular WS. Erythema could be noticed especially in phototype IV, and may correlate with the presence of symp- toms, like pruritus as we noticed in three of our patients with ALP. On the other hand, in the resolution phase, WS are ab- sent, with fine or coarse gray-blue, brown or brown -black dots on a brown background [5,16]. WS are therefore a good marker of therapeutic efficiency that disappears with 8 Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 International Dermoscopy Society reported dermoscopy of the pigmented form of lichen actinicus with the main dermo- scopic feature as periosteal brown dots and brown structure- less areas with ostial sparing [10]. This descriptive study of dermoscopic patterns of various subtypes of ALP highlighted new dermoscopic descriptions that vary according to the clinical variant or the morphology, lesions distribution, and the phototype. Also, some epidemi- ological differences were noticed in comparison with the previous publications, concerning the older age of onset in melasma-like pigmented ALP, and the male predominance in annular ALP. Other prospective studies with a large number treatment. Pigmented structures could however resist treat- ment, which was also noticed in our ALP patients (Figure 7). Dermoscopic particularities of ALP were not fully de- scribed and investigated, only three publications [1,5] exist in the literature (Table 1). One concerned the annular vari- ant of ALP, another reported a case of macular ALP that was misdiagnosed as lentigo maligna, due to the overlap- ping dermosopic patterns found in the two diagnoses, es- pecially the melasma-like ALP , such as diffuse peppering, hyperpigmented follicular openings, signet ring-like sign, and circles with central black dots [1], and an interesting study of non-neoplastic dermatoses in skin of colour by the Figure 9. Plaque-like Actinic Lichen Planus dermoscopy: follicular white halo (red circle) surrounded by a pigmented rim, and pigmented dots arranged in parallel lines (blue arrow). In less elevated areas, we notice dots inside circles (blue circle), eccentric pigmentation on circles (blue rectangle), and circumferential radial lines at the periphery of the plaques (blue star). Figure 10. Dyschromic Actinic Lichen Planus on the dorsum of the hands. Black hole pat- tern (blue circle) with annular Wickham striae and brown-grayish globules in the center. Central follicular plugs in some of the lesions (blue arrow), and dotted vessels with a radial linear distribution on the Wickham striae (red arrow). Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 9 Table 1. Dermatoscopic differences between Actinic Lichen Planus and classic Lichen Planus with a dermoscopy patology correlation Dermoscopic signs Classic lichen planus Actinic lichen planus Dermatopathologic correlations of dermatoscopic findings Wickham striae (18) • Dark phototype (19,20) Polymorphic pearly white structures (rounded, arbori- form, reticular, annular), Blue-white White circular and reticular White-yellow-bluish WS Hypergranulosis with acanthosis Pigmented structures Active lesions Active ad late lesions Annular granular pattern Not described Pigmented melasma-like ALP Melanin incontinence Dots inside circles Not described Pigmented melasma-like ALP Eccentric pigmentation on circles Not described Pigmented melasma-like ALP Blue-gray granules Yes Pigmented melaslma-like ALP Periosteal brown dots and brown structureless areas with ostial sparing (10) Not described Pigmented ALP Hypopigmentation lacking skin creases Not described Pigmented melasma-like ALP Irregular acanthosis. and hypergranulosis Perifollicular white halos Not described AALP and plaque-like ALP Early perifollicular fibrosis Follicular plugs Hypertrophic forms of LP AALP and plaque-like ALP Follicular hyperkeratosis White scales Yes, may be diffuse obscuring the visibility of shiny white structures and Wickham striae Fine scales Orthokeratosis Shiny white structures (19) Reticular lines, and structurless areas Reticular lines and perifollicular in AALP and plaque-like ALP Dermal fibrosis Circumferential radial lines at the periphery Not described AALP and plaque-like ALP Peripheral extension of the basal vacuolization, the dermal inflammatory infil- trate and the pigmentary incontinence Pigmented dots arranged in parallel lines Not described AALP and plaque-like ALP Melanin incontinence Vascular structures Radial capillaries with dotted, globular and/or lin- ear vessels, mainly localized at the periphery of the lesion (and less commonly showing a perifollicular or a diffuse pattern) (21) Dotted vessels in Dyschromic ALP Dermal vessels Background Pink violet, reddish and blue–gray, brown or yellow background Light to dark brown violaceous blue–gray background ALP = Actinic Lichen Planus; AALP = annular Actinic Lichen Planus; LP = Lichen Planus. 10 Original Article | Dermatol Pract Concept. 2024;14(2):e2024101 Dermoscopy Society. Eur J Dermatol. 2020;30(6):688-698. DOI: 10.1684/ejd.2020.3928. PMID: 33319764. 11. Cengiz FP, Cengiz AB, Emiroglu N, Comert E, Wellenhof RH. Der- moscopic and clinical features of head and neck melanoma. An Bras Dermatol. 2015;90(4):488-493. DOI: 10.1590/abd1806- 4841.20153341. PMID: 26375217. PMCID: PMC4560537. 12. Kelati A, Rimani M, Chiheb S. Dermoscopy of Annular Atro- phic Lichen Planus on a Dark Phototype: A Case Series. Der- matol Pract Concept. 2023;13(1):e2023024. DOI: 10.5826/ dpc.1301a24. PMID: 36892367. PMCID: PMC9946049. 13. Kamyab K, Gholi Z, Ghiasi M, Pirzadeh M, Nasimi M. Clin- icopathological Study of 307 Patients with Lichen Planus Ac- tinicus and Pigmentosus Referred to Razi Skin Hospital From 2016 to 2021. Dermatol Pract Concept. 2023;13(2):e2023119. DOI: 10.5826/dpc.1302a119. PMID: 37196290. PMCID: PMC10188149. 14. Denguezli M, Nouira R, Jomaa B. Le lichen plan actinique. Etude anatomo-clinique de dix observations tunisiennes [Actinic lichen planus. An anatomoclinical study of 10 Tunisian cases]. Ann Dermatol Venereol. 1994;121(8):543-546. PMID: 7755310. 15. Aloi F, Solaroli C, Giovannini E. Actinic lichen planus sim- ulating melasma. Dermatology. 1997;195(1):69-70. DOI: 10.1159/000245692. PMID: 9267745. 16. MMakhecha M, Singh T, Malladi N, Rambhia K. Dermoscopic features of various stages of lichen planus. Indian J Dermatol Venereol Leprol. 2020;86(2):191-194. DOI: 10.4103/ijdvl.IJ- DVL_931_18. PMID: 32056976. 17. García-García B, Munguía-Calzada P, Aubán-Pariente J, Argen- ziano G, Vázquez-López F. Dermoscopy of lichen planus: Vascu- lar and Wickham striae variations in the skin of colour. Australas J Dermatol. 2019;60(4):301-304. DOI: 10.1111/ajd.13052. PMID: 30982948. 18. Dash S, Behera B, Palit A, Sethy M, Nayak AK, Ayyanar P. Der- moscopy of lichen planus under polarized vs. nonpolarized mode: a retrospective analysis of 14 patients. Clin Exp Der- matol. 2021;46(4):752-756. DOI: 10.1111/ced.14565. PMID: 33484573. 19. 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