Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept 2021;11(1):e2021111 1 Dermatology Practical & Conceptual Acquired Brachial Cutaneous Dyschromatosis: A Rarely Recognized Condition Jorge Román-Sainz1, Sergio Samer Tabbara-Carrascosa1, Marta Martínez-García1, Adrián Imbernón-Moya1 1 Dermatology Unit, Hospital Universitario Severo Ochoa, Leganés, Spain Key words: dyschromatosis, poikiloderma, sun damage, hyperpigmentation, pigmentary disorders Citation: Román-Sainz J, Tabbara-Carrascosa ST, Martínez-García M, Imbernón-Moya A. Acquired brachial cutaneous dyschromatosis: a rarely recognized condition. Dermatol Pract Concept. 2021;11(1):e2021111. DOI: https://doi.org/10.5826/dpc.1101a111 Accepted: June 22, 2020; Published: January 29, 2021 Copyright: ©2021 Román-Sainz et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License BY-NC-4.0, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: None. Competing interests: The authors have no conflicts of interest to disclose. Authorship: All authors have contributed significantly to this publication. Corresponding author: Jorge Román-Sainz, MD, Travesía de Téllez, 8, 7º R, 28007, Madrid, Spain. Email: jorgesheldon@gmail.com Introduction Acquired brachial cutaneous dyschromatosis (ABCD) is a pig- mentary disorder located on the forearms, especially affecting middle-aged women aged 50-70 with Fitzpatrick’s phototype III-IV [1]. There are only 23 cases reported in the literature, although it is likely underreported by patients due to its lack of symptoms [2]. Case Presentation A 71-year-old woman, with skin type III was referred to the Dermatology Unit for a 6-month history of asymptomatic skin lesions on her forearms. She reported intense, chronic sun exposure. She was being treated with lisinopril, an angioten- sin converting enzyme (ACE) inhibitor, due to hypertension. Dermatological exploration showed confluent, symmetrical, light brown hyperpigmented and hypopigmented macules with linear and oval morphology and cutaneous atrophy (Fig- ure 1). Skin biopsy revealed a preserved epidermis with slight hyperpigmentation of the basal layer, and a few telangiectases at the dermal level with marked actinic elastosis. The patient was diagnosed with acquired brachial cutaneous dyschroma- tosis (ABCD). Photoprotection was prescribed, and she had partial improvement of the lesions after 6 months. Conclusions ABCD was first reported by Rongioletti and Rebora in the year 2000 [1]. It is an acquired pigmentary disorder that presents as asymptomatic light brown patches interspersed with hypopigmented macules [1]. Histology shows poikilo- dermatous tissue with hyperpigmentation of the basal layer, solar elastosis, and superficial telangectases [1,2]. Most of the reported cases present bilaterally on the distal aspect of the forearms [1]. Twenty cases were reported (85%) in females, with only 3 cases in males [1,2]. The age of onset ranged from 50-70, and 91% of cases have been reported in patients with skin phototype III-IV, with only 2 cases being a type II [1,2]. An 2 Image Letter | Dermatol Pract Concept 2021;11(1):e2021111 association with Civatte poikiloderma was found in 9 (39%) patients [1]. The incidence and prevalence of this disorder are unknown. ABCD is thought to be an underdiagnosed disease, likely due to lack of consultation by the patients. There are currently 2 hypotheses about the etiopatho- genesis of ABCD. The first one states that ABCD is related to chronic treatment with ACE inhibitors; 14 (60%) patients were reported to have been in treatment with such drugs for years [1]. The other theory claims that ABCD is more related to cumulative sun damage, as most of the patients had evi- dence of chronic sun exposure [2]. Both hypotheses could explain the cause of ABCD in a majority of these cases, and this is likely due to an interaction between ACE inhibitors and sun exposure in predisposed patients. Differential diagnosis must include Civatte poikiloderma, melasma, postinflammatory hyperpigmentation, pigmented contact dermatitis (Berloque dermatitis), macular amyloido- sis, prurigo pigmentosa, and drug-induced hyperpigmenta- tion. Although these disorders may be clinically similar, they can be easily differentiated with histopathogical examination. There is no standard treatment for ABCD. Strict photo- protection is the most widely recommended, but a combina- tion of topical depigmenting agents, chemical peels, and laser treatments can be considered [2]. References 1. Rongioletti F, Rebora A. Acquired brachial cutaneous dyschroma- tosis: a common pigmentary disorder of the arm in middle-aged women. J Am Acad Dermatol. 2000;42(4):680-684. DOI: 10.1067/ mjd.2000.103273. PMID:10727320. 2. Choi MJ, Byun JY, Choi HY, Choi YW. Acquired brachial cu- taneous dyschromatosis in a middle aged male. Ann Derma- tol. 2018;30(3):342-344. DOI: 10.5021/ad.2018.30.3.342. PMID:29853750. Figure 1. (A) Clinical image showing linear hyperpigmented macules with atrophic and poikilodermal skin. (B) Histopathological image showing epidermal atrophy, as well as hyperpigmentation of the basal layer, solar elastosis, and telangiectases at the superficial dermis. A B