Obesity and the skin

Question 1

What are some skin functions that are affected by obesity?

Answer 1

• Wound healing
• Barrier function
• Skin blood flow
• Lymphatic drainage
• Hormone production
• Sebum production

Question 2

How does obesity cause a decrease in wound healing?

Answer 2

Failure of collagen deposition to match the increased surface area in obesity leads to altered collagen structure and function

Question 3

How does obesity affect the skins barrier function?

Answer 3

Obesity decreases the barrier function of the skin as there is increase trans-epidermal water loss, leading to dry skin

Obesity can result in enlarged skin folds, in which ther is increased activity of apocrine and eccrine glands

This increases moisture, skin maceration and friction which increases irritation

Question 4

How does obesity affect skin blood flow?

Answer 4

Obesity is associated with microvascular dysfunction, resulting in increased skin blood flow, which may contribute to hypertension

Question 5

How does obesity affect lymphatic drainage of the skin?

Answer 5

Pressure from fat impeded lymphatic flow and causes leakage of protein rich lymphatic fluid into sub-cutaneous tissues

Question 6

How does obesity affect hormone production?

Answer 6

The endocrine roles of adipose tissue may be altered in obesity, with increased hormone production (E.g. testosterone)

Question 7

How does obesity affect sebum production?

Answer 7

Increased androgens produced in this peripheral fat can stimulate sebaceous glands

Question 8

What are some direct skin manifestations of obesity?

Answer 8

Acanthosis nigricans
Skin tags (acrochordons)
Hirsutism
Acne
Hidradenitis suppurative
Androgenic alopecia
Stretch marks (Striae distensae)

Question 9

What is acanthosis nigricans?

Answer 9

A velvety thickening and pigmentation of skin folds, usually in the axillae

Question 10

Where are skin tags most commonly found?

Answer 10

Axillae
Neck areas

Question 11

What is hidradenitis suppurative?

Answer 11

A chronic inflammatory disease where boils and abscesses form and scar in apocrine gland areas (E.g. axillae, groin)

Question 12

What are stretch marks?

Answer 12

Type of scarring associated with dermal connective tissue injury in response to local stretching forces (E.g. rapid weight gain in pregnancy and obesity)

Question 13

What causes acanthosis nigricans and skin tags in obesity?

Answer 13

They are linked to insulin resistance

Question 14

What causes hirsutism, acne, hidredenditis suppurativa and androgenic alopecia in obesity?

Answer 14

hyper-androgenism (Increased male hormone levels due to increased production in fat)

Question 15

What are some skin conditions that can be aggravated by obesity?

Answer 15

• Lymphoedema
• Chronic venous insufficiency
• Skin infections
• Intertigo
• Psoriasis

Question 16

How does obesity worsen lymphoedema?

Answer 16

1. Increased subcutaneous fat causes reduced lymphatic drainage leading to swelling
2. Gradually worsening swelling causes chronic inflammation, leading to fibrosis
3. Reduced tissue oxygenation and swelling results in bacterial overgrowth
4. Cellulitis develops easily and leads to further lymphatic damage
5. A downward spiral develops if left untreated and ultimately the skin becomes thick and warty and the lower leg and foot become permanently enlarged, often grossly

Question 17

How does obesity worsen chronic venous insufficiency?

Answer 17

1. Abdominal obesity resists venous return form the legs
2. Veins dilate and valves become incompetent, causing development of varicose veins
3. Increased hydrostatic pressure in the vessels results in red cell leakage into the tissue, causing swelling, haemosiderin pigmentation and inflammation (Venous dermatitis)
4. Chronic scarring eventually occurs
5. Skin may ulcerate (Venous ulceration)

Question 18

How does obesity worsen skin infection?

Answer 18

There is an increased tendency to bacterial, fungal and yeast infections, especially in skin folds and areas where circulation is affected (E.g. legs)

Question 19

What is intertrigo?

Answer 19

Intertigo are macerated red plaques which develop in the skin folds due to increased moisture levels, friction and increased pH, with reduced barrier function and increased risk of secondary infection

Question 20

How does obesity aggravate psoriasis?

Answer 20

The link is unknown between psoriasis and obesity, but psoriasis morbidity is higher in obesity and weight control plays a role in management

Flexural psoriasis is aggravated by obesity