Dermatology Flashcards
What is the average area of the skin?
2 square metres
How much does the skin weigh?
4-5kg
What is the average thickness of skin
1-2mm
What are the three layers of the skin?
- Epidermis
- Dermis
- Subcutaneous layer
Skin structure
Epidermis structure
What is acne?
Characterised by formation of comedones (black and whiteheads) and spots known as papules and pustules
What causes acne?
Inflammation of the pilosebaceous units of skin
What factors can combine to form acne?
- Rise in sebum secretion in response to sex hormones in adolescence
- Overgrowth of bacterium in follicular duct
- Formation of bacterial plug blocking follicle
- Inflammation caused by body’s immune response
What are the four main skin changes in acne?
- Open comedomes - blackheads
- Closed comedomes - whiteheads, completely blocked follicle
- Papules - red or flesh-coloured bumps on surface of skin
- Pustules - white or yellow pus-filled pimples
How is acne classified by severity?
Mild - comedomes, papules/pustules
Moderate - papules, pustules, nodules
Severe - scarring, nodulocystic acne
What are the aims of acne treatment?
- Reduce sebum secretion
- Prevent blockage of the pilosebaceous duct
- Reduce or eliminate colonisation by P. acnes
- Reduce inflammation
How were the recommendations for the treatment of acne produced by the Guidance Alliance to Improve Outcomes in Acne in 2003 updated in 2009?
Reduced reliance on antibiotics and increased focus on acne as a chronic
What topical therapies can be used for acne?
Benzyl peroxide
Retinoids - reduce sebum production and inflammation
Comedolytics and keratolytics - soften hard keratin and slowing shedding of skin cells
Topical antibiotics - erythromycin and clindamycin
What are the effects of topical medicines used to treat acne?
What oral therapies can be used to treat acne?
Oral ABX - tetra, oxytetra, doxy or lymecycline
Hormonal - COC, co-cyprindiol
Retinoids isotretinoin
What is rosacea?
Chronic skin condition that affects the face. Begins with episodes of facial flushing, may progress to acne-like symptoms as well as thickened, bumpy skin and eye problems
How is rosacea classified?
Type 1-4
How is type 1 rosacea classified?
Erythematolangiectatic - flushing and redness around centre of face. May also see swelling and red blood vessels, rough patches of skin, burning and stinging sensations
How is type 2 rosacea classified?
Papulopustular - persistent redness around centre of face, with bumps and pimples resembling acne. Burning and stinging may also occur. Often seen after or in combo with type 1
How is type 3 rosacea classified?
Phymatous - thickened skin with bumpy surface. Most often affects nose (rhinophyma)
How is type 4 rosacea classified?
Red, irritated eyes. Feeling like there is something in eye, burning, dryness, light sensitivity, blurred vision. May occur with or without rosacea
What are the triggers of rosacea?
Exposure to sunlight Stress Exercise Cold weather (wind) Heat Menopause Vasodilator drugs Hot drinks Alcohol and caffeine Spicy foods
What are the topical treatments for mild rosacea?
Topical ABX - metronidazole, sodium sulfacetamide to treat pustules
Topical comedolytic agents - azelaic acid to unblock pores and reduce inflammation
What oral treatments can be used to treat moderate-to-severe rosacea?
ABX - tetracyclines or erythromycin
Retinoids - isotretinoin
What is dermatitis?
Immunological, inflammatory reaction in skin. Many different forms, including eczema. Can be acute or chronic
What are exogenous factors?
Those outside the body that cause disease e.g. chemical in soap, sunlight
What are endogenous factors?
Those within the body that cause disease
What are some types of dermatitis and what ages to they affect?
What is irritant contact dermatitis?
Skin reaction where causative agent is external. Immediate or cumulative reaction, irritation occurs once chemicals are able to penetrate the keratinous part of skin and trigger inflammatory immune response within dermis cells
What are characteristics of irritant contact dermatitis?
Rash - localised to area of exposure, may be erythematous (reddened), inflamed, itchy, swollen. Small vesicles may be present. Prolonged exposure gives cracked, scaly skin
What is allergic contact dermatitis?
Hypersensitivity reactions which has potential to appear on other parts of body as well as area directly exposed to allergen
What are the stages of development of allergic dermatitis?
- An allergen enters skin and encounters Langerhans cells, found scattered in epidermis
- These take up the allergen which pass on the identification to T-cells
- T-cells multiply, circulate round body and begin to accumulate at site of reaction
- If allergen still detected, T-cell activated and respond by releasing variety of inflammatory molecules , causing redness, swelling, inflammation
What is atopic eczema?
Most common form of eczema. Chronic. Inflammation and disruption of various layers throughout skin
Skin initially itchy, flaky, erythematous and dry in acute phase
Thickened, cracked and crusted as condition progresses
What gene is atopic eczema associated with?
Filaggrin gene
What is seborrhoeic dermatitis in infants?
Caused by overactive sebaceous glands and results in oily skin. Common in nappy area or head
Not itchy or sore however secondary infection may occur
What is seborrhoeic dermatitis in adults?
Affects areas where there are most sebaceous glands (face, scalp, chest), but sebum secretion appears normal
What factors cause adult seborrhoeic eczema?
Genetic and endogenous factors which permit excessive growth of a yeast Malassezia furfur
What is an un-inflamed form of seborrhoeic dermatitis?
Dandruff