Nutrition and the Skin Flashcards
Define allergy
symptom caused by an immune reaction, usually IgE mediated, but sometimes non-IgE (thought to be T cell mediated but not well understood
Define intolerance
non-immune reaction e.g. lactose intolerance where there is enzyme deficiency leading to poor breakdown of lactose in the GI tract, causing symptoms.
How does obesity affect collagen structure and wound healing?
reduced mechanical strength of skin in obesity is due to a failure of collagen deposition to match the increased surface area
How does obesity impact skin barrier function?
Increased trans-epidermal water loss so skin tends to be dry
How does obesity affect sebaceous glands?
Increased androgens produced in peripheral fat sitmulate sebaceous glands
How does obesity affect subcutaenous fat?
endocrine roles of subcutaenous fat may be altered in obesity with increased hormone production e.g. testosterone
How does obesity affect lymphatics?
Pressure from fat impedes flow and causes leakage of protein-rich lymphatic fluid into subcutaenous tissues
How does obesity affect circulation?
Associated with microvascular dysfunction resulting in increased blood flow to the skin which may contribute to hypertension
How does obesity affect apocrin and eccrine glands?
Increased activity in large skin folds increases moisture/skin maceration and friction in folds increases irritation
What is acanthosis nigricans?
- Direct skin manifestation of obesity
- velvety thickening and pigmentation in skin folds, usually axillae
What are acrochordons?
- direct skin manifestation of obesity
- skin tags
- frequently found in axillae and neck area
- both associated with higher circulating insulin levels due to reduced peripheral sensitivity
What is hirtuism?
- direct skin manifestation of obesity
- increased hair in femals in a male distribution
How does obesity precipitate acne?
Increased sebaceous gland activity
What is hidradenitis suppurativa?
- direct skin manifestation of obesity
- chronic inflammatory condition where boils and abscesses form and scar in apocrine gland areas (axillae, groin)
What is androgenetic alopecia?
- Male pattern baldness in men/women
- direct skin manifestation of obesity
What are striae distansae?
- direct skin manifestation of obesity
- dermal connective tissue injury in response to local stretch
Describe the sequence of events in lymphoedema aggravated by obesity?
- Increased subcutaenous fat causes reduced lymphatic drainage, leading to swelling
- gradually worsening swelling causes chronic inflammation leading to fibrosis
- reduced tissue oxygenation and swelling results in bacterial overgrowth
- cellulitis develops easily and leads to further lymphatic drainage
- downward spiral develops if left untreated and ultimately skin becomes thick and warty and the lower leg and foot becomes permanently enlarged, often grossly
Describe the sequence of events in chronic venous insufficiency?
- abdominal obesity resists venous return from the legs
- veins dilate and valves become incompetent, varicose veins develop
- increased hydrostatic pressure in the vessels results in red blood cell leakage into the tissue resulting in swelling, haemosiderin pigmentation and inflammation (due to break-down products) i.e. venous or stasis dermatitis
- chronic scarring eventually occurs
- the skin may ulcerate- venous (stasis) ulceration
What is intertrigo?
Macerated red plaques which develop in skin folds due to high moisture levels, friction, pH and reduced barrier function and are prone to secondary infection
What is the link between obesity and psoriasis?
Unclear link?!
Psoriasis morbitidy higher in obesity and weight plays a role in managment
Flexular psoriasis is aggravated by obesity
What is marasmus?
- global nutrient deficiency causing weight loss by fat breakdown
- The child is very thin with muscle wasting.
- There is no oedema.
- The skin is dry, wrinkled and loose from subcutaneous fat and muscle loss.
- Hair is thin, brittle and falls out easily; causing alopecia.
What is Kwashiorkor?
- thought to be caused by low protein intake with reasonable carbohydrate intake, there is oedema and children often develop an enlarged pot belly.
- skin shows irregular or patchy discolouration caused by pigmentary change.
- Dark, dry skin may split when stretched, revealing pale areas between the cracks (crazy paving dermatosis)
What is the skin presentation of Vitamin A deficiency?
keratotic follicular papules on the thighs and upper arms, dry skin
What are good sources of vitamin A?
Animal: milk, liver, eggs, oily fish
Plant: green leafy veg, bright orange/yellow fruit and veg
