Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2023;13(4):e2023235 1 Hyperpigmentation Induced by Hydroxychloroquine Laila Hamri1 1 Department of internal medicine, provincial hospital center Sidi Hsein Bennacer, Ouarzazate, Morocco Citation: Hamri L. Hyperpigmentation Induced by Hydroxychloroquine. Dermatol Pract Concept. 2023;13(4):e2023235. DOI: https://doi.org/10.5826/dpc.1304a235 Accepted: April 15, 2023; Published: October 2023 Copyright: ©2023 Hamri. 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: Laila Hamri, Department of internal medicine, provincial hospital center Sidi Hsein Bennacer, Ouarzazate, Morocco. Tel : 00212660834013 Mail : laila.medic@gmail.com Case Presentation A 52-year-old Moroccan woman, with a previous diagnosis of Sjogren syndrome (SS), presented to our internal medicine consultation with the appearance of hyperpigmented lesions on lower lip and back of hands (Figure 1). She was medi- cated with hydroxychloroquine for 4 years at a dose of 400 mg/day. Clinical examination did not show any other local- izations. She did not present any other clinical systemic sign suggesting diagnosis of systemic lupus erythematosus. Con- sidering her age, clinical context and current medications, the main diagnoses that were evoked were drug-induced hyperpigmentation, metabolic disorders, endocrinopathies, other auto-immunities, and a paraneoplastic syndrome. We performed biological tests: blood cell count, 8-hour cortisol level, TSH, red blood cell sedimentation, C-reactive-protein, serum iron, ferritin, AST, ALT, bilirubin, gGT, PAL, urea, creatinine, anti-phospholipid antibodies, 24-hour protein- uria, blood and urine ionograms, virus serologies (HCV, HIV, HBV), ceruleoplasmin, and vitamin B12 levels. A tho- racic-abdominal-pelvic CT scan was also requested to rule out a neoplastic origin. As for the immunological workup, anti-SSA and anti-SSB were initially positive, but these same antibodies were found when the immunological tests were redone. Furthermore, biological and radiological investi- gations came back normal, and the diagnosis of hyperpig- mentation induced by hydroxychloroquine was retained. An ophthalmological examination with a visual field was car- ried out, objective an enlargement of the blind spot, with- out other abnormality. Hydroxychloroquine was definitively 2 Image Letter | Dermatol Pract Concept. 2023;13(4):e2023235 discontinued. Two months later, we noted a stability of the lesions, without appearance of other locations. Teaching Point Antimalarials are responsible for hyperpigmentation in 25% to 33% of cases [1]. This side effect is much more com- mon with chloroquine and quinacrine than with hydroxy- chloroquine [1]. The most characterized locations are the oral cavity, the neck and the front of the legs [1,2]. It ap- pears after months or years of use of the molecule, and it is dose-dependent [1]. Hydroxychloroquine-induced retinop- athy is commonly associated. Discontinuation of the drug generally allows clearing of the lesions after a few months. It is important to rule out differential diagnoses, including other iatrogenic causes, endocrinopathies (Addison disease, Cushing syndrome, hyperthyroidism), metabolic disorders (hemochromatosis, Wilson disease), infections (HIV, Derma- tophytes), nutritional disorders [1]. References 1. Wang, Rebecca F., Dayoung Ko, Ben J. Friedman, Henry W. Lim, et Tasneem F. Mohammad. Disorders of Hyperpigmentation. Part I. Pathogenesis and Clinical Features of Common Pigmen- tary Disorders. J Am Acad Dermatol. 2023;88(2):271-288. DOI: 10.1016/j.jaad.2022.01.051. PMID: 35151757. 2. Tosios KI, Kalogirou EM, Sklavounou A. Drug-associated hyper- pigmentation of the oral mucosa: report of four cases. Oral Surg Oral Med Oral Pathol Oral Radiol. 2018;125(3):e54-e66. DOI: 10.1016/j.oooo.2017.10.006. PMID: 29287748. Figure 1. (A,B) Hyperpigmentation of lower lip (A) and back of hands (B) induced by hydroxychloroquine.