Greetings. Your child seems to be over weight for her age and hence has developed features of acanthosis nigricans due to insulin resistance. The diagnosis can be confirmed after examining the child or seeing the photos. Please see a qualified dermatologist. Also you'll need to get the child evaluated by a pediatrician / pediatric endocrinologist. Make sure you minimise junk food to your child and encourage her to indulge in physical activities. Hope this helps. Warm regards. Dr Govind Suresh Mittal, Bengaluru