Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2024;14(1):e2024032 1 Unilateral Verrucous Psoriasis Successfully Treated With Adalimumab Artur Antônio Duarte1, Ana Gabriella Bandeira Freire Andrade1, Caroline Costa de Mendonça1, Mônica Ramos de Freitas1, Dimitri Luz Felipe da Silva1 1 University of Santo Amaro, São Paulo, Brazil Key words: psoriasis, adalimumab Citation: Antônio Duarte A, Andrade AGBF, Costa de Mendonça C, Ramos de Freitas M, Luz Felipe da Silva D. Unilateral Verrucous Psoriasis Successfully Treated With Adalimumab. Dermatol Pract Concept. 2024;14(1):e2024032. DOI: https://doi.org/10.5826/ dpc.1401a32 Accepted: June 23, 2023; Published: January 2024 Copyright: ©2024 Antônio Duarte 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: Ana Gabriella Bandeira Freire Andrade, University of Santo Amaro, São Paulo, Brazil. E-mail: anagabriellabandeira@gmail.com Introduction Verrucous psoriasis (VP) is a rare variant of psoriasis that typically arises in patients with established psoriasis but can occur de novo [1]. There is a higher prevalence in men [2]. The disease usually appears in areas of friction, and is associated with obesity, diabetes mellitus, and peripheral circulatory failure [3]. We report a case of unilateral verrucous psoriasis with a good response to treatment with adalimumab. Case Presentation A 31-year-old female patient reported pruritic scaly erythem- atous lesions over the body for 5 years. Previous betameth- asone with salicylic acid cream without improvement of the lesions was used. She had a personal history of obesity grade II and was asthmatic using formoterol fumarate dihydrate plus budesonide. Dermatological examination found scaly erythematous plaques with thick, verrucous-like crusts, well adherent in the lower left quadrant of the abdomen, left breast (medial upper quadrant) and left axilla. The lesions followed Blaschko lines and did not extend beyond the mid- line (Figure 1). A skin biopsy showed regular psoriasiform acanthosis of the epidermis, widening of the bases of the interpapillary ridges, thinning of the suprapapillary portion, laminar hy- perparakeratosis containing Munro microabscesses, Kogoj spongiform pustule in the epidermis and dilatation, capillary tortuosity in the papillary dermis (Figure 2). Clinical and histopathological findings led to the di- agnosis of unilateral verrucous psoriasis. Treatment with clobetasol, methotrexate oral and UVB-NB phototherapy was started with partial response. Adalimumab (40 mg ev- ery two weeks) was then opted out and showed efficacy of 90% (psoriasis area severity index [PASI] 90) after 12 weeks (Figure 3). 2 Research Letter | Dermatol Pract Concept. 2024;14(1):e2024032 Conclusions VP is characterized by symmetric hypertrophic verrucous plaques that may have an erythematous base and involve the legs, arms, trunk, and dorsal aspect of the hands; malodor is frequent [4]. It has been hypothesized that marked hyperkeratosis is induced by repeat trauma to the extremities in patients with established psoriasis or by anoxia from conditions that predispose to poor circulation, such as diabetes mellitus and pulmonary disease [3]. The diagnosis of VP can be challenging because of its similarity to other entities, including verruca vulgaris; epi- dermal nevus; contact dermatitis, eczema, fungal infection and squamous cell carcinoma [4,5]. Histopathologically, overlapping features of verruca vulgaris and psoriasis have been described [2,4]. Regarding treatment, this condition is sometimes refrac- tory. Use of topical therapies such as corticosteroids and ker- atolytics has minimal response in monotherapy. The greatest successes reported so far have been with systemic therapy such as methotrexate and acitretin, used alone or in combi- nation [4]. As for immuno-biologicals, the few reported cases showed only a partial response. However, the unilateral variant of VP is even more un- common, with only one case reported in the literature so far. In this case, only topical treatment was chosen, as the patient refused systemic therapy. We report the first case of unilateral verrucous psoriasis that, after refractoriness to treatment with topical cortico- steroids, phototherapy and oral methotrexate, showed an excellent response to the immuno-biological Adalimumab, Figure 1. (A) Verrucous psoriasis on the left side of the abdomen. (B) Verrucous psoriasis of the breast and left armpit. Figure 2. (H&X10) Regular acanthosis with a psoriasiform pattern, thinning of the suprapapillary portion, Kogoj spongiform pustule in the epidermis and capillary dilation and tortuosity in the papillary dermis. Figure 3. Significant improvement of verrucous lesions after 2 months of use of adalimumab with few residual nodular lesions. Research Letter | Dermatol Pract Concept. 2024;14(1):e2024032 3 reaching PASI 90 after 12 weeks of treatment. Therefore, we aim to contribute to the recognition of this entity and pro- mote more assertive therapeutic alternatives. References 1. Sanyal RD, Vyas NS, Sapadin AN, Phelps RG. Unilateral Verrucous Psoriasis. Cutis. 2021;107(2):97-98. DOI: 10.12788 /cutis.0174. PMID: 33891840. 2. Rejeb SB, Dhaoui A, Ghachem DB, Souissi A, Bellil K. Psoriasis with verrucous appearance: a case report. Our Dermatology On- line. 2017;8(1):63–65. DOI: 10.7241/ourd.20171.17 3. Khalil FK, Keehn CA, Saeed S, Morgan MB. Verrucous Psori- asis: A Distinctive Clinicopathologic Variant of Psoriasis. Am J Dermatopathol. 2005;27(3):204-207. DOI: 10.1097/01.dad .0000157450.39033.31. PMID: 15900122. 4. Shivers L, Montanez-Wiscovich ME. Verrucous psoriasis treated with methotrexate and acitretin combination therapy. Cutis. 2019;104(6):E10-E12. PMID: 31939936.