Acanthosis nigricans: a marker for hyperinsulinemia

Acanthosis nigricans in middle-age adults: A highly prevalent and specific clinical sign of insulin resistance

BACKGROUND

Insulin resistance (IR) precedes the diagnosis of many metabolic and non-metabolic illnesses, including type 2 diabetes mellitus (T2DM). Acanthosis nigricans (AN) is a clinical sign associated with IR. However, AN prevalence and diagnostic accuracy in middle-age adults before or at the time of prediabetes/diabetes diagnosis remain uncertain.

METHODS

With the aim to define AN prevalence and diagnostic accuracy, adults between 40 and 60 years of age were consecutively invited to participate in the study. Participants were categorised into one of two main groups: individuals with normoglycaemia (group 1) and hyperglycaemia (group 2 [ie, prediabetes/diabetes]). Demographic, clinical, anthropometric characteristics, homeostasis model assessment of IR, homeostatic model assessment of β-cell function, as well as the presence of AN on the neck, axillae, elbows and knuckles were assessed.

RESULTS

A total of 320 consecutive participants with a mean age of 49.3 years (59.4% women) were included. Overall, AN prevalence was 46.3%, while AN in group 1 and group 2 was 36.3% and 49.6%, respectively (P = .04). The most common affected sites in group 1 (n = 80) were the knuckles (21.2%) and the neck (17.5%), while in group 2 (n = 240), the neck (29.6%) followed by the knuckles (26.7%). The specificity and positive predictive value of AN for IR were 0.85 and 0.86 in group 1 and 0.90 and 0.96 in group 2, respectively.

CONCLUSIONS

In middle-age adults, within the entire spectrum of carbohydrate tolerance, AN is highly prevalent and specific. This finding supports its assessment as a reliable and convenient clinical sign of IR. The understanding of AN behaviour through different carbohydrate tolerance strata, and its different locations, could lead to early detection of individuals at high metabolic risk or help direct a more pathophysiological treatment approach in patients with T2DM.

Acanthosis nigricans in the knuckles: An early, accessible, straightforward, and sensitive clinical tool to predict insulin resistance

Any clinical/biochemical marker revealing obesity or diabetes before their appearance is valuable. Insulin resistance (IR) is present in both disorders many years before occurrence. Accordingly, we determined whether acanthosis nigricans (AN) in the knuckles is associated to higher insulin and homeostasis model assessment for estimated insulin resistance (HOMA-IR) index values, and assessed the influence of body-mass index (BMI) and the diagnostic performance of AN in the knuckles to detect IR. In this cross-sectional controlled study, we included men or women, 18 to 23 years old, with or without AN in the knuckles. In 149 cases with AN in the knuckles and 145 controls, fasting insulin was higher in cases (13.45 µU/mL ± 7.8 vs. 8.59 µU/mL ± 3.63, P < .001, respectively). Mean HOMA-IR index was also higher (2.86 ± 1.68 vs. 1.78 ± 0.77, P < .001). A significant increase in fasting insulin and HOMA-IR values between and within BMI groups from normal through obese category was identified in controls and cases. By multivariate regression analysis, cases with normal BMI were significantly associated to a HOMA-IR ≥2.5 (OR = 3.09, CI95% = 1.75-5.48, P = .001). A model of AN in the knuckles, normal BMI, and increased waist circumference allowed identifying 2 out of 3 cases with HOMA-IR index ≥2.5. AN in the knuckles could be addressed with two aims: as an easy, accessible, and costless diagnostic tool suggesting hyperinsulinemia secondary to IR, and, an early marker of IR even in the absence of overweight or obesity.

Acanthosis nigricans in obese adolescents: prevalence, impact, and management challenges

Obesity in adolescence is a public health priority because it usually tracks into adulthood, resulting in enormous medical and social costs. This underscores the importance of early identification and intervention. Acanthosis nigricans (AN) was once considered a rare paraneoplastic dermatosis, but is now frequently observed in obese adolescents. Current understanding suggests that it is associated with insulin resistance and has a unique role in secondary prevention. The purpose of this narrative review is to provide a comprehensive overview of AN in obese adolescents, covering its history, current knowledge on the condition, its clinical significance, management challenges, and the direction of future research.

Hypochondroplasia, Acanthosis Nigricans, and Insulin Resistance in a Child with FGFR3 Mutation: Is It Just an Association?

FGFR3 mutations cause wide spectrum of disorders ranging from skeletal dysplasias (hypochondroplasia, achondroplasia, and thanatophoric dysplasia), benign skin tumors (epidermal nevi, seborrhaeic keratosis, and acanthosis nigricans), and epithelial malignancies (multiple myeloma and prostate and bladder carcinoma). Hypochondroplasia is the most common type of short-limb dwarfism in children resulting from fibroblast growth factor receptor 3 (FGFR3) mutation. Acanthosis nigricans might be seen in severe skeletal dysplasia, including thanatophoric dysplasia and SADDAN syndrome, without a biochemical evidence of hyperinsulinemia. Insulin insensitivity and acanthosis nigricans are uncommonly seen in hypochondroplasia patients with FGFR3 mutations which may represent a new association. We aim to describe the association of hypochondroplasia, acanthosis nigricans, and insulin resistance in a child harboring FGFR3 mutation. To our knowledge, this is the first case report associating the p.N540 with acanthosis nigricans and the second to describe hyperinsulinemia in hypochondroplasia. This finding demonstrates the possible coexistence of insulin insensitivity and acanthosis nigricans in hypochondroplasia patients.

Dermatologic manifestation of diabetes

With the rising incidence of diabetes mellitus (DM) in the US, it is of paramount importance that practitioners understand the complications of DM and how best to manage them. Diabetes affects every organ system and the skin is no exception. There are numerous cutaneous manifestations of DM that have similar etiologies and result from the same pathologic mechanisms as the internal complications of this disease state. In addition, skin manifestations may precede the diagnosis of diabetes. The present article reviews both the common and less common cutaneous manifestations of DM, including presenting lesions, pathogenesis, and management.

Pediatric nonalcoholic fatty liver disease: A clinical and laboratory challenge

The true prevalence of pediatric nonalcoholic fatty liver disease (NAFLD) is unknown. Challenges in determining the population prevalence of NAFLD include the type of test (and the reference intervals used to define normal and abnormal), the type of population (general population, hospital series), the demographic characteristics of the population sampled, and the nature of the study design. The natural history of pediatric NAFLD remains uncertain. The issue of when to perform a liver biopsy in children with suspected NAFLD remains controversial. Children with NAFLD but normal alanine aminotransferase are rarely investigated. However, evidence of alterations in glucose metabolism parameters should prompt a better understanding of the natural history of pediatric NAFLD not only in terms of the progression of liver disease but also regarding its potential relationship with other health outcomes such as type 2 diabetes mellitus and cardiovascular disease. This evidence could make liver biopsy mandatory in the majority of cases at risk of progressive and severe hepatic and extrahepatic disease. This conclusion, however, raises the question of the feasibility of liver biopsy assessment in an extremely large at risk population, and of the cost/effectiveness of this policy. There is a considerable, continuous interest in reliable, noninvasive alternatives that will allow the prognosis of pediatric NAFLD to be followed in large community or population-based studies.

Novel phenotypic markers and screening score for the metabolic syndrome in adult Asian Indians

AIMS

The metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) are common in Asian Indians. Simple yet reliable phenotypic markers are needed for early detection of the MS in Asian Indians.

METHODS

In this cross-sectional study, 126 subjects either with of without the MS were compared. Anthropometric measurements (including assessment of novel phenotypic markers) and metabolic profile were done.

RESULTS

On univariate analysis, age more than 35 year, female gender, presence of buffalo hump and double chin and family history of T2DM were significantly associated with the MS. A metabolic syndrome screening (MSS) score (1.0 x double chin+1.2 x buffalo hump+1.3 x gender+1.4 x age category) was generated with a cutoff value of 3.5 out of total points of 4.9, with sensitivity and specificity 82% and 71% [area under the curve=0.83; 95% confidence Interval (0.76-0.90)], respectively in detecting individuals with the MS.

CONCLUSION

We describe buffalo hump and double chin as novel phenotypic markers for detection of MS for the first time. The MSS score generated by us may be a useful tool for detection of MS in adult Asian Indians; however, it needs further validation in a larger sample of Asian Indians and in other ethnic groups.

Dermatologic manifestations of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) affects 5-10% of reproductive-aged women and is one of the most common endocrine disorders in women. The disorder is commonly characterized by elevated levels of androgen and insulin. Women with PCOS may present with a range of signs and symptoms, and face increased risks of reproductive, metabolic, cardiovascular, psychologic, and neoplastic sequelae, particularly if the condition is left unrecognized or untreated. The clinical definition of PCOS has changed in recent years and includes as one of its cardinal criteria the dermatologic manifestations of hyperandrogenism, chiefly hirsutism, acne vulgaris, and androgenetic alopecia. Acanthosis nigricans, a cutaneous sign of hyperinsulinemia, may also be present. These dermatologic features may provide early clinical clues to recognition of PCOS, and treatment of these cutaneous conditions may improve the patient's quality of life and psychologic well-being. The effects of androgen on pilosebaceous units in the skin can vary by anatomic location, producing pathophysiologic effects on hair growth and differentiation, sebaceous gland size and activity, and follicular keratinization. Treatment modalities may include hormonal therapy intended to modulate androgen production and action as well as non-hormonal therapies directed toward specific dermatologic conditions.

Nonalcoholic fatty liver disease in children

Nonalcoholic fatty liver disease (NAFLD) is likely to reach epidemic proportions in children worldwide in the next decade. NAFLD may be the hepatic aspect of the metabolic syndrome in adults and children. The entire range of liver involvement characterizing NAFLD can occur in children: hepatic macrovesicular steatosis without inflammation, steatosis with inflammation or fibrosis, and cirrhosis. NAFLD may be more severe in children from certain ethnic groups or in association with metabolic disorders characterized by abnormalities in insulin receptor structure and function. Treatment strategies focus on modifying risk factors because specific drug treatments are lacking. Overweight/obesity should be identified as early as possible. Comprehensive clinical management to normalize weight should be instituted immediately to avoid hepatic and nonhepatic complications.

Acanthosis nigricans associated with insulin resistance : pathophysiology and management

The association of acanthosis nigricans, skin tags, diabetes mellitus due to insulin resistance, and obesity in adolescents and young adults represents a well defined syndrome. Hyperandrogenism may also be present. The endocrine origin of this condition is beyond doubt. Insulin and insulin-like growth factor-1, and their receptors on keratinocytes are obviously involved in the complex regulations leading to the peculiar epidermal hyperplasia. This condition is unrelated to other types of acanthosis nigricans, including the congenital and the paraneoplastic types. Control of obesity contributes largely to reverse the whole process, essentially by reducing both insulin resistance and compensatory hyperinsulinemia. Several drugs including metformin, octreotide, retinoids and topical colecalciferol (vitamin D(3)) analogs are also beneficial in clearing acanthosis nigricans.

Acanthosis Nigricans in Kabuki Syndrome

BACKGROUND

Acanthosis nigricans has been classified in different ways. All classifications depend on the clinical picture and the association with other conditions.

OBJECTIVE

We report a case of acanthosis nigricans in a patient with Kabuki syndrome. This syndrome is characterized by five main manifestations: typical facial features, post natal growth deficiency, skeletal abnormalities, dermatoglyphic abnormalities, and mild to moderate mental retardation.

CONCLUSION

Our case may suggest that acanthosis nigricans could be associated with Kabuki syndrome.

Steatohepatitis in children

Steatohepatitis in children occurs in the childhood version of non-alcoholic fatty liver disease (NAFLD), as a result of hepatotoxicity and with certain genetic/metabolic diseases. Until recently, NAFLD was considered to be rare in children. It is now recognized as an important childhood liver disease, especially because childhood obesity is much more common. Children with NAFLD may present as young as 4 years old; males tend to predominate; fibrosis is often found on liver biopsy and cirrhosis has been reported. Treatment for childhood NAFLD currently consists of weight reduction plus regular aerobic exercise; vitamin E may be an effective adjunctive therapy. Drug hepatotoxicity and genetic/metabolic diseases that can cause fatty liver, such as Wilson's disease and cystic fibrosis, must be excluded since treatment is radically different. Other causes of chronic hepatitis, such as chronic viral hepatitis, must also be excluded. Multisystemic inherited diseases with hyperinsulinaemia plus insulin resistance may have NAFLD as hepatic involvement and should be identified.

Generalized acanthosis nigricans in early childhood

Acanthosis nigricans (AN) is a disorder often accompanied by internal malignancy in adult patients, but in children it is usually benign. Generalized forms of AN, especially in childhood, are extremely rare. We report a 5-year-old boy with a 3-year history of AN who had generalized roughness and hyperpigmentation, numerous skin wrinkles, disseminated skin tags, tripe palms, and intensive pruritus. No clinical evidence of internal disorders, notably of an endocrinologic or neoplastic nature, have been detected thus far.

Nonalcoholic steatohepatitis in children

BACKGROUND

Nonalcoholic steatohepatitis occurs commonly in adults with obesity or diabetes mellitus. There are only a few reports of this condition in children.

METHODS

Prospective consecutive clinical series.

RESULTS

Between December 1985 and April 1995, 36 children (21 boys, 15 girls) were diagnosed with nonalcoholic steatohepatitis at the Hospital for Sick Children, Toronto. The median age at diagnosis was 12 years (range, 4-16 years). Most patients were referred because of elevated serum aminotransferases or abnormal hepatic sonogram. Thirty patients (83%) were obese. Two patients had diabetes mellitus at diagnosis, and it developed later in two. Fifteen patients had palpable hepatomegaly, and one of these had splenomegaly. None had physical signs of chronic liver disease. Thirteen of 36 patients had acanthosis nigricans. Serum aminotransferases were elevated in all but one patient. Tests for Wilson disease and chronic hepatitis B and C were negative. Serum lipid profiles were abnormal in 18 patients: 7 had hypercholesterolemia, and 11 had hypertriglyceridemia. Twenty-four of 31 examined had abnormal liver sonograms suggestive of fatty infiltration. Twenty-four patients underwent percutaneous liver biopsy: all showed large-droplet fat. Inflammation was present in 88% and fibrosis-cirrhosis in 75%. One 10-year-old patient had established cirrhosis at diagnosis.

CONCLUSIONS

Nonalcoholic steatohepatitis occurs in children, is clinically diverse, and may not be benign.