Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2024;14(4):e2024279 1 Acrodermatitis Continua of Hallopeau Successfully Treated With Bimekizumab Andrea Pagliara1,2, Federico Bardazzi1, Lidia Sacchelli1, Federica Filippi1,2, Camilla Loi1, Bianca Maria Piraccini1,2, Giacomo Clarizio1,2 1 IRCCS Azienda Ospedaliero-Universitaria di Bologna Policlinico di Sant’Orsola, Dermatology Unit 2 Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy Key words: bimekizumab, Psoriasis treatment, Biological therapy, TNF-α, Hallopeau Citation: Pagliara A, Bardazzi F, Sacchelli L, et al. Acrodermatitis Continua of Hallopeau Successfully Treated With Bimekizumab. Dermatol Pract Concept. 2024;14(4):e2024279. DOI: https://doi.org/10.5826/dpc.1404a279 Accepted: July 18, 2024; Published: October 2024 Copyright: ©2024 Pagliara 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: Andrea Pagliara, IRCCS Azienda Ospedaliero-Universitaria di Bologna Policlinico di Sant’Orsola, Dermatology Unit and Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna. E-mail: andrea.pagliara7@studio.unibo.it Introduction Acrodermatitis continua of Hallopeau (ACH) is a rare form of pustular psoriasis characterized by recurrent eruptions of sterile pustules localized on the distal phalanges of hands and feet that can induce onychodystrophy and anonychia as well as osteolysis of the affected phalanges [1]. Case Presentations A 74-year-old Caucasian man came to Consultation present- ing pustular lesions involving all the fingers of the hands and the toes. On clinical observation, onychodystrophy of some nails of the hands along with pustules and edema were pres- ent (Figure 1). The patient also complained of joint mobility limitation and pain. The patient was already being followed in our department for a mild form of plaque psoriasis in- volving the trunk and the limbs, with an on-demand topical therapy. During the last 3 years lesions were spread on the hand, but the trunk was spared. The patient was first treated with adalimumab 40 mg every other week for 6 months, with unsatisfactory results. One year later, he came back to Consultation with an evident form of ACH involving the 10 fingers and feet. Thus, we decided to start a therapeutic protocol with bimekizumab 320 mg administered subcu- taneously every 4 weeks. After the first administration, the clinical aspect had improved considerably: the erythema and the pustules had almost completely disappeared, the edema retrieved, and the patient regained the mobility of flexion- extension of the fingers (Figure 2). His quality of life has sig- nificantly improved, as the social impact of the uncontrolled pathology was extremely disabling. Subsequently, a 47-year-old Caucasian female patient, also diagnosed with ACH, was treated with suspended brodalumab (initially treated with adalimumab and secuki- numab) and was started on the same regimen (bimekizumab 320 mg). A subtotal remission was obtained after the second administration and is still maintained to date. 2 Research Letter | Dermatol Pract Concept. 2024;14(4):e2024279 Finally, an 86-year-old Caucasian female patient with a diagnosis of ACH involving some fingers had obtained no response with adalimumab after 6 months and was started on bimekizumab as aforementioned. Clinical response was good after the second administration. Conclusions These cases contribute to expanding current knowledge about this pathology that is not seen frequently and of which management is still not standardized. The excellent clinical response of the patients to the therapy provides further in- formation regarding not only the pathogenetic mechanisms underlying ACH but also the medical management. There are no randomized clinical trials or case series regarding the use of bimekizumab in ACH. In scientific literature, there exists a documented case regarding bimekizumab in ACH in which improvement was gained in 2 months [2]. In our expe- rience, after 6 months of treatment, this molecule has proved to be safe, effective, but above all, quick to act compared to other treatments. References 1. Ranugha PS, Kumari R, Thappa DM. Acrodermatitis continua of hallopeau evolving into generalised pustular psoriasis. Indian J Dermatol. 2013;58(2):161. DOI:10.4103/0019-5154.108096. 2. Cirone KD, Lovegrove FE. Acrodermatitis continua of Hallopeau successfully treated with bimekizumab: A case report.  SAGE Open Med Case Rep. 2023; 11:2050313X231160937. Published 2023 Mar 21. DOI:10.1177/2050313X231160937. Figure 1. Pustules and onychodystrophy affecting all the distal fingers and nails of the hands. Figure 2. Almost complete improvement after only 1 administration of bimekizumab, a month after the start of the therapy.