Introduction to Dermatology Flashcards by Elaine Brazier

What is the biggest organ in the body?

The skin

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How many skin conditions make up 70% of all skin disease in the Uk?

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What are these 9 skin conditions?

Acne
Atopic eczema
Benign tumours/lesions
Contact Dermatitis
Leg Ulcers
Psoriasis
Skin Cancer
Skin Infections
Viral Warts

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What are the 3 big layers of the skin (external to internal)?

Epidermis
Dermis
Fat and connective tissue (sub. cut.)

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What are the 5 layers of the epidermis (external to internal)?

Stratum corneum
Stratum lucidum
Granular cell layer
Spinous cell layer
Stratum basale/Basal cell layer

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What main structures does the dermis contain?

Blood vessels
Nerves
Hair follicles
Lymphatics
Glands (sweat, apocrine, sebaceous)

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What does the skin act as a barrier to?

Microbes
Chemicals
UV light
Antigens
Water loss

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What does the skin use to regulate temperature?

Sweat glands

Changes in blood flow

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What biochemical functions do sweat glands have?

Vitamin D synthesis

Androgen pro-hormone conversion

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Whatr other functions does skin have?

Protection of internal structures
Sensation
Immune surveillance
Communication

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What 5 Ds are important in the impact of skin disease?

Disability, discomfort, depression, disfigurement, and death

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What symptoms can skin disease cause?

Pain
Itching
Discomfort
Redness
Bleed
Weeping
Crusting
Blister
Burn

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What can be used to measure the impact of skin disease? (2)

Dermatology Life Quality Index (DLQI)

Psoriasis Area Severity Index (PASI)

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What features are important in taking a dermatology history WRT patient demographics?

Age

Ethnicity

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What FH is important to ask in a dermatology history?

Inherited skin diseases
Communicable infection within family unit
Previous exposure to specific skin diseases (eg VZV)

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What social history is important to take in a dermatology setting?

Infection risk
Occupation
Recent travel
Smoking and alcohol

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What equipment is used to exmine the skin?

A dermatoscope (plus your eyes and hands)
A good light
Measuring tape
Woods light

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What is important in a history for a solitary lesion?

Age of pt
Duration
Change over time (size, shape, colour)
Hx of similar lesion and treatment
FH of skin cancer

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Where should be examined in a dermatology consultation?

All over - where the lesion is, plus all the skin including nails, scalp, behind ears, and inside mouth

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What distribution may a skin problem manifest in?

Widespread/localised
Grouped/scattered
Symmetrical or not
Pattern (eg dermatomal)
Sparing

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What is the Koebner phenomenon?

Typically associated with psoriasis and a few other skin conditions, a patch of skin initially unnvolved develops lesions due to cutaneous trauma

i.e. i scratch my skin, loads of psoriatic lesions form where my nails went

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Apart from position, shape and size, how else should a solitary lesion be described?

Surface texture
Consistency
Fixed/Immobile
Warm/pulsatile

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What is a wheal?

A very itchy, evanescent, circumscribed area of redness/oedema; characteristic of hypersensitivity and/or anaphylactic reaction

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What is the difference between an erosion and an ulcer?

The depth - an erosion is more superficial, the ulcer penetrates the skin deeper

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What is a fissure?

Where thick patches of skin affected by psoriasis crack

What is an excoriation?

Skin abrasions, usually superficial, due to scratching of the skin

Which layer of the skin varies the most? How?

The stratum corneum - it varies in thickness according to where on the body it is

How big is a papule?

Less than 5mm across

How big is a ndoule?

5-10mm

What is a vesicle? What is a bulla?

Respectively, a small and a large water blister

What is a pus-filled vesicle called?

A pustule

What is telangiectasia?

A threaded vein

What is alopecia?

Hair loss/thinning

What is hairiness known as?

Hirsutism

What are striae?

Stretch marks

What is pruritus?

Itching

What is a macule?

A non palpable area of discolouration

What is a patch?

A macule over 2cm

Describe the Fitzpatrick skin types.

Type 1 - white, always burn never tan. Type 2 - white, usually burn, difficult to tan. Type 3 - white, sometimes burn, average tan. Type 4 - moderate brown, rarely burn, tan with ease. Type 5 - dark brown, rarely burn, tan very easily. Type 6 - black, does not burn, tan very easily

When taking a derm history, what acronym do we use for pigmented lesions?

ABCDEF

What do the letters in the acronym for pigmented lesions stand for?

``` Asymmetry Border irregular Colour (multiple/uniformity) Diameter Evolution Funny looking/ugly duckling ```

Why is a drug history important in dermatology?

May have skin manifestation of reaction to a new or regular drug.

When is a drug most likely to cause a reaction which shows up on the skin?

Between 2 days and 2 weeks after starting the drug. Although they can cause a derm presentation at any time.

When describing a skin lesion, what acronym can we use to remember what we need to look at/report?

SCAM

What does SCAM stand for?

Site, size, and shape Colour Associated changes Morphology

After examining the skin, what else do we need to examine?

Systemically - anywhere where there are other symptoms, look at nail changes, the hair, and mucous membranes.

A 60 year old woman presents with an itchy rash on her left ankle for several months. O/E there is an erythematous asymmetrical patch across both ankles with skin thickening and excoriations. What is your top differential?

Venous/Stasis eczema

How should venous/stasis eczema be managed?

Strong topical steroids Compression stockings to help with congestion Treat underlying cause

What is the most commonly used strong topical steroid?

Dermovate

A teenage girl presents with a lesion on her chin. O/E the lesion is well dermarcated and asymmetrical with a yellow crust. What is your top differential?

Impetigo

A teenage girl presents with multiple lesions on her chin. O/E the lesions are blisters/bullae on an erythematous base. What is your top differential?

Bullous impetigo

What does actinic keratosis look like?

Base of fair, sun-damaged skin. Skin is rough and erythematous, with scale and multiple keratinic lesions.

How should impetigo be managed?

Topical application of vaseline and antibacterials to gently remove crust. Remove crust regularly. Topical antibiotics are usually sufficient

What antibiotics are normally used topically for impetigo?

Fusidic acid and mupirocin (for MRSA)

What is a skin appendage?

A structure formed by skin-derived cells

What are the skin appendages?

Hair Nails Sebaceous glands Sweat glands

What are the 4 major cell types in the epidermis?

- Keratinocytes - Melanocytes - Langerhans' cells - Merkel cells

What is the main function of the keratinocytes of the epidermis?

Produce keratin which forms a protective barrier

What is the main function of the melanocytes of the epidermis?

Produce melanin to pigment the skin and protect cell nuclei from UV induced DNA damage

What is the main function of the Langerhans' cells of the epidermis?

Immune protection (antigen presenting cells)

What is the main function of the Merkel cells of the epidermis?

Contain specialised nerve endings for sensation

How long is the average epidermal turnover time?

30 days

What is the dermis made up of?

Collagen (mainly) Elastin Glycosaminoglycans

What are the 3 main types of hair?

- Lanugo hair (fine long hair in foetus - Vellus hair (fine short hair on body surface) - Terminal hair (coarse hair on scalp/eyebrows/eyelashes/pubic areas)

Describe the structure of a hair.

Made of modified keratin. 2 parts - the hair shaft and the hair bulb. Shaft = keratinised tube Bulb = actively dividing cells with melanocytes for pigmentation

What are the 3 stages of the hair cycle?

- Long growing phase - Short regressing phase - Resting/shedding phase

What is the nail plate made of?

Hard keratin

Where does the nail plate arise from?

The nail matrix at the posterior nail fold

Where does the nail plate rest?

On the nail bed

What are a sebaceous gland and a hair follicle known as together?

Pilosebaceous unit

What are sebaceous glands activated by?

Conversion of androgens to dihydrotestosterone i.e. become active at puberty

What are the 2 types of sweat gland?

Ecfrine and aprcrine

Where are eccrine sweat glands found?

Universally distributed over skin

Where are apocrine sweat glands found?

Axillae Areolae Genitalia Anus Modified glands also found around external auditory canal.

What are the 4 phases of wound healing?

- Haemostasis - Inflammation - Proliferation - Remodelling

By what mechanisms is haemostasis achieved as part of wound healing?

- Vasoconstriction - Platelet aggregation - Clot formation

What cells are involved in the inflammation part of wound healing?

Neutrophils and macrophages are recruited

Why are neutrophils and macrophages recruited in the inflammation stage of wound healing>

For phagocytosis

How does the inflammation stage differ from the haemostasis stage in terms of blood supply?

There is vasodilation (-> rubor/calor etc) instead of vasoconstriction for haemostasis

What are the 2 processes that occur in the prolferation phase of wound healing?

- Granulation tissue formation and angiogenesis | - Re-epithelialisation

How does the remodelling phase of wound healing occur?

Through collagen fibre re-organisation and scar maturation

Once skin lesion has been examined, where else should be examined? Why?

The skin appendages - nails, scalp, hair, and mucous membranes. A systems review should also be done. For any further signs of disease or systemic involvement.

Generally speaking, how much cream/ointment is needed to cover the whole adult body area?

30 grams

How much surface area does one fingertip unit cover?

The area of 2 palms = 0.5 grams

What lesions can we take skin swabs from?

``` Vesicles Pustules Erosions Ulcers Mucosal surfaces ```

For what lesions might a skin scrape be done?

A scaly lesion

How is a skin scrape performed?

Gentle use of a scalpel if fungal infection or scabies is suspected.

What surgical skill is used in dermatology?

Ankle-brachial pressur index measuring

Why is an ABPI done?

To identify presence and severity of peripheral arterial insufficiency

To which conditions is an ABPI measurement significant?

Leg ulcers (arterial or venous)

Which pressure are measured in an ABPI?

- Dorsalis pedis/posterior tibila artery | - Brachial artery

What is a normal ABPI?

Over 0.8

How is the ABPI calculated?

Ratio of highest ankle pressure to highest brachial pressure of the 2 arms.

When would an ABPI be inappropriately high?

In a pt with calcified vessels e.g. in diabetics.

Introduction to Dermatology Flashcards

(94 cards)