Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2024;14(3):e2024187 1 Chik Sign With Dermoscopic Findings in 10 Patients With Dengue: Case Series Bhavya Sangal1, Shruti Barnwal1, Devi Priya1, Astha Pant1, Aditi Vashisht1 1 Department of Dermatology, Government Doon Medical college, Dehradun, India Key words: chik sign, dengue fever, pigmentation, dermoscopy, chikungunya Citation: Sangal B, Barnwal S, Priya D, Pant A, Vashisht A. Chik Sign With Dermoscopic Findings in 10 Patients With Dengue: Case Series. Dermatol Pract Concept. 2024;14(3):e2024187. DOI: https://doi.org/10.5826/dpc.1403a187 Accepted: April 10, 2024; Published: July 2024 Copyright: ©2024 Sangal 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: Dr. Bhavya Sangal, MD (Dermatology, Venereology and Leprosy) DNB, Assistant Professor, Department of Dermatology, Government Doon Medical College, Dehradun, Uttarakhand, India, Pin 248001. E mail:bhavyasangal@gmail.com Introduction Dengue and chikungunya are two arboviral diseases that are endemic in many parts of the world. The chik sign is a cutaneous manifestation of chikungunya fever that is char- acterized by brownish hyperpigmentation of the nose that is hypothesized to occur due to deposition of intraepidermal melanin triggered by the virus [1]. It has been rarely reported in patients with dengue fever, but prevalence of this cutane- ous manifestation with dermoscopic findings in this disease is not well described in literature [2]. This case series reports 10 patients with dengue fever who presented with the chik sign along with their dermoscopic findings. Case Presentation Ten patients (7 females and 3 males) with a mean age of 24 years, presented in the Dermatology Outpatient Department of a tertiary care hospital in India complaining of pigmenta- tion on and around nose. There was history of fever in all the patients 2-3 weeks before onset of pigmentation accompa- nied with maculopapular erythematous rash,headache and muscle pain. There was no history of drug intake or history of prior dermatoses. On examination asymptomatic hyper- pigmented macules and patches (chik sign) were seen on the nasal alae (10 patients) (Figure 1A), dorsum of the nose (9 patients), bilateral cheeks (3 patients), and bilateral palms (1 patient). There was no mucosal involvement.All pa- tients had a positive dengue NS1 antigen test and dengue IgM antibody test. Dermoscopic findings (Dinolite premier AM4113ZT) showed a pseudo-reticular pigment network, brown globules with brownish background, patulous follic- ular openings, and perifollicular accentuation of pigmenta- tion (Figure 1B). Hydroquinone cream 2% along with strict sunprotection was advised for all adult patients with good results at the end of 6 weeks. Conclusions Dengue fever is an arboviral disease which is associated with cutaneous and mucosal findings like confluent erythema, morbilliform eruptions, and hemorrhagic lesions in differ- ent phases of disease [2]. In this case series, all patients pre- sented with chik sign and dengue as a cause of fever was 2 Research Letter | Dermatol Pract Concept. 2024;14(3):e2024187 confirmed by performing dengue serology and NS1 antigen testing. Other causes of hyper-pigmentationwere directly, or indirectly, ruled out in our case series. The chiksign has been known to be associated with chi- kungunya fever. The postulated cause of hyperpigmentation may be attributed to increased intraepidermal melanin, dis- persion or retention triggered by the virus [3]. Some authors consider the chik sign as post inflammatory hyperpigmenta- tion which is further aggravated by ultraviolet ray exposure since the face is the most common site of the lesions [4-5]. We hypothesize the same reason for the hyperpigmented lesions seen in patients of dengue and this series provides further evidence that the chik sign can occur in patients with dengue. Table 1 highlights dermoscopic changes in close differen- tials of the chik sign, which are sebomelanosis, melasma, and lichen planus pigmentosus. All cases except the infant were treated with 2% hydro- quinone cream and strict sun protection. In conclusion, the chiksign in dengue fever is an underre- ported entity, and dermoscopy further aids in differentiating it from other hyperpigmentary disorders. Figure 1. (A) Chik sign on nose. (B) Dermoscopic findings: perifollicular pigment accentuation (stars), patulous follicular openings with a brown background (arrows). Table 1. Comparison of Dermoscopic Findings of Melasma, Lichen Planus Pigmentosus, Sebomelanosis, and Chik Sign Melasma Lichen Planus Pigmentosus Sebomelanosis Chik Sign Background Dark hyperpigmentation Faint hyperpigmentation with occasional erythema Hyperpigmented to erythematous background Brown background Reticular network Exaggerated pseudo-network Accentuated uniform/ nonuniform Prominent pseudo- network with erythema at margins Hyperpigmented pseudonetwork with perifollicular accentuation of pigment. Other Brown dots and globules, annular and arcuate structures, telangiectasia Evenly spaced-out brown to gray dots and globules Yellowish scales, telangiectasia, whitish yellow excrescences of sebum coat the hair follicles Patulous follicular openings, few brown globules Research Letter | Dermatol Pract Concept. 2024;14(3):e2024187 3 Dermatol 2017;3:289-292. DOI: http://dx.doi.org/10.18203 /issn.2455-4529.IntJResDermatol. PMID: 20172214. 4. Kumar R, Sharma MK, Jain SK, Yadav SK, Singhal AK. Cuta- neousmanifestations of chikungunya fever: observations from an outbreak at aTertiary Care Hospital in Southeast Rajasthan, India. Indian Dermatol Online J2017;8:336–42. DOI: 10.4103 /idoj.IDOJ_429_16. PMID: 28979866. 5. Vinay K, Ankad BS. Dermatoscopic features of pigmentary dis- eases in ethnic skin. Indian Dermatol Online J 2021;12:24–33. doi: 10.4103/idoj.IDOJ_561_20. PMID: 33768020 References 1. Bhatia SS, Shenoi SD, Hebbar SA, Kayarkatte MN. The chik sign in dengue. Pediatr Dermatol. 2019;36(5):737-738. DOI: 10.1111/pde.13883. PMID: 31260132. 2. Thomas EA, John M, Kanish B. Mucocutaneous manifesta- tions of dengue fever. Indian J Dermatol. 2010;55:79-85. DOI: 10.4103/0019-5154.60359. PMID: 20418984. 3. Chavan RB, Sakunke AS, Belgaumkar VA, et al. Varied cutane- ous manifestations of chikungunya fever: a case series. Int J Res