Which of the following about bronze baby syndrome is not true

Bronze baby syndrome is a rare complication seen in neonates with hyperbilirubinemia who are being treated with phototherapy. Affected neonates develop gray-brown skin, serum, and urine within a week of initiation of phototherapy. All neonates with bronze baby syndrome have hyperbilirubinemia necessitating phototherapy, and most have concomitant liver dysfunction.It involves the trunk and extremities. The exact cause of the gray-brown discoloration in bronze baby syndrome is unceain. Products may accumulate as a result of poor excretion secondary to liver dysfunction. The discoloration presents after exposure to phototherapy and fades after phototherapy is discontinued. Reference: GHAI Essential pediatrics, 8th edition