#obesity and #skin - the association between some dermatologic disorders and the overweight.

Obesity is a public health problem in the industrialized world. It is defined by a BMI (Body Mass Index) of more than 30 Kg/m2. In the United States, it is estimated that  30% of individuals are overweight or obese (BMI more than 25)

It is known that obese individuals have an increased incidence of:

1. hypertension
2. diabetes mellitus (especially type 2)
3. dyslipidemia
4. depression
5. ischaemic cardiopathy.

Moreover, obesity is associated with several skin problems:

• striae distensae (stretch marks)

• plantar hyperkeratosis

• skin tags (acrochordons): the number and size of the lesions are directly linked to the degree of obesity. The development of these lesions is highly associated with insulin resistance. 

• intertrigo (inflammatory process in the folds) + fungal infections of the inflammed skin by dermatophytes and candida. 

• keratosis pilaris (hyperplasia follicularis)

• pseudoacanthosis nigricans: it is a benign form of acanthosis nigricans which affects more often individuals with a darker skin color. It begins at puberty and is associated with obesity and insulin resistance. It regresses once the metabolic disturbances are corrected. 

• lymphedema: the obstruction of the natural lymphatic drainage channels by fat tissue is responsible for the lymphatic stasis, that causes swelling of the lower limbs.

• bacterial infections (cellulitis and erysipelas), due to lymphatic stasis + insulin resistance. 

• psoriasis: this chronic inflammatory disease is clearly associated with the metabolic syndrome (hypertension, diabetes mellitus, dylipidaemia). Besides, it is also known that the severity of psoriasis is proportional to the BMI.