Clinicoepidemiological study of acanthosis nigricans in pre and primary school children and its association with body mass index, waist circumference and insulin resistance

Abstract

Acanthosis nigricans is characterised by hyperpigmentation and velvet like thickening of skin. It is seen symmetrically involving the neck, axilla, groins, antecubital and popliteal fossae, umbilical, perianal areas and in advanced conditions, even dorsum of hands and fingers.To evaluate the clinical features and epidemiological factors of acanthosis nigricans in pre and primary school children and to evaluate the association of acanthosis nigricans with body mass index, waist circumference and insulin resistance. A total of 100 children with acanthosis nigricans meeting defined inclusion and exclusion criteria were enrolled in this cross-sectional study after taking an informed consent and approval of institutional ethical committee. All parents of children with acanthosis nigricans were subjected to a detailed history based on a questionnaire. A thorough clinical examination was done to study acanthosis nigricans. Blood samples were collected and fasting serum insulin and fasting blood sugar were determined. Most of the children were boys (M:F=1.3:1) and mean age was 6.66±1.99 years. Twenty four percent were normal weight, 28% were overweight and 48% were obese children. On examination, neck was the commonest site of acanthosis nigricans. Grade 4 neck severity (p=0.0014) and grade 3 neck texture (P=0.0198) of acanthosis nigricans were significantly associated with Insulin resistance (HOMA2-IR). Twenty eight percent of normal weight, 42.8% of overweight and 75% of obese children had insulin resistance. Acanthosis nigricans was associated with insulin resistance in normal, overweight and obese children. Hence, we would like to propose that all the children with acanthosis nigricans must be screened for Insulin resistance irrespective of body mass index. With this evidence of Insulin resistance, guidelines can be given to the parents about life style modification which will help in preventing the onset of diabetes mellitus later and thereby, improving the quality of life of the child.