Chik sign in a neonate: a distinctive manifestation of vertically transmitted chikungunya

¹Department Kaumarbhritya, Mahatma Gandhi Ayurved College Hospital and Research Centre, Salod (H), Datta Meghe Institute of Higher Education and Research, Deemed to be University, Wardha, Maharashtra, India

^&Corresponding author
Faiz Ahmad Mohammad Firoz Shah, Department Kaumarbhritya, Mahatma Gandhi Ayurved College Hospital and Research Centre, Salod (H), Datta Meghe Institute of Higher Education and Research, Deemed to be University, Wardha, Maharashtra, India

Image in medicine    

A term female neonate, birth weight 3 kg, born via normal vaginal delivery, presented on day 6 of life with fever, poor feeding, and jaundice. She was initially managed as late-onset sepsis with suspected meningitis after developing convulsions. Cerebrospinal fluid examination revealed elevated protein and low glucose levels. Despite escalation of antibiotics, the infant developed a characteristic rash on day 12 of life, consisting of mixed hyperpigmented and hypopigmented macules over the face and trunk. The baby also exhibited excessive irritability and adopted a frog-leg posture with pain on passive limb extension, suggestive of severe arthralgia. On detailed antenatal history, the mother reported fever with erythematous rash one day prior to delivery, followed by severe arthralgia postpartum. This raised suspicion of congenital chikungunya, which was confirmed by positive RT-PCR in the neonate. Congenital chikungunya is a rare but important cause of neonatal illness presenting with sepsis-like features, neurological manifestations, and characteristic pigmentary skin changes. Vertical transmission is strongly associated with maternal viremia in the peripartum period, with symptoms typically appearing between days 3-7 of life. Characteristic clinical features include centrofacial hyperpigmentation, maculopapular rash, seizures, apnea, and marked irritability due to arthralgia, often resulting in a frog-leg posture. Early recognition based on maternal history and distinctive neonatal findings is essential for accurate diagnosis.

Figure 1: A) mixed hyperpigmented and hypopigmented macules over the face, neck, and upper chest of the neonate, showing the distinctive “chik sign;” B) frog leg posture adopted by the neonate, reflecting irritability and pain due to arthralgia