OBESITY

Obesity is more than being considerably overweight.
• Body Mass Index (BMI) is calculated by dividing a person’s body weight in kilograms by the height in meters squared (weight [kg] height [m]2) or by using the conversion with pounds (lbs) and inches (in) squared.

[Weight (lbs) ÷ height (in)2 ] x 704.5 =BMI

The BMI cutoffs are:
Below 18.5              Underweight
18.5-24.9                 Normal weight
24.5-29.9                 Overweight
30 and greater         Obese
40 and greater         Morbid or extreme obesity

• Waist circumference is another widely used measurement to determine abdominal fat content. An excess of abdominal fat, when out of proportion to total body fat, is considered a predictor of risk factors related to obesity.
  • Men with a waist measurement exceeding 40 inches
  • Women with a waist measurement of 35 inches or greater. (adapted from The Obese Society Guidelines)

Being fat also affects the skin in several ways:

• Acanthosis nigricans – dark, furry patches on the nape and in the axillae (Figure 1)
• Circulatory problems
  • Elephantiasis
  • Lymphedema
  • Stasis dermatitis (Figure 2)

Figure 1: Acanthosis nigricans due to obesity

Figure 2: Stasis dermatitis aggravated by obesity

• Cutaneous infections
  • More common
  • Candidosis (yeast infection)
  • Erythrasma
  • Folliculitis
  • Furunculosis
  • Intertrigo (Figure 3)
  • Tinea cruris (jock itch)
  • Less common
  • Cellulitis
  • Gas gangrene
  • Necrotizing ceullulitis
• Plantar hyperkeratosis
• Psoriasis
• Skin tags (acrochordons, fibro-epthelial polyp) – small, pedunculated lesions, most often on the neck or in the axillae. More frequently, associated with obesity

Figure 3: Intertrigo and striae resulting from obesity

• Striae (stretch marks) (Figure 3)
• Sweat gland afflictions
  • Hidradenitis suppurativa
  • Hyperhidrosis
• Syndromes
  • Laurence-Moon-Biedl-Bardet syndrome (hypogonadism, mental retardation, obesity, polydactyly, renal failure, and retinitis pigmentosa)
  • Prader-Willi syndrome (preoccupation with food and constant hunger, hypotonia (floppy baby syndrome), delayed mental development obesity and obesity–related health problems, and stunted growth cognitive delays).

Noah Scheinfeld, MD, JD
New York, NY