Dermatology Flashcards
Define pruritus
Itching
Define lesion
Area of altered skin
Define naevus
Localised malformation of tissue structure (mole)
Define comedone
Plug in sebaecous follicle containing altered sebum, bacteria and cellular debris
Can present as either open (blackhead) or closed (whitehead)
Define flexural
In body fold
Define Koebner phenomenon
Linear eruption arising at site of trauma
Define discrete
Individual lesions separated from each other
Define confluent
Lesions merging together
Define annular
Circle or ring
Define discoid/nummular
Coin shaped/round lesion
Define erythema
Redness which blanches on pressure
Define purpura
Red or purple colour which does not blanch on pressure
- petechiae = small pinpoint macules
- ecchymoses = larger bruise like patches
Define hypopigmentation
Areas of paler skin
Define depigmentation
White skin due to absence of melanin
Define hyperpigmentation
Darker skin
Define macule
Flat area of altered colour
Define patch
Larger flat area of altered colour or texture
Define papule
Solid raised lesion < 0.5cm in diameter
Define nodule
Solid raised lesion > 0.5cm in diameter with a deeper component
Define plaque
Palpable scaling raised lesion > 0.5cm in diameter
Define vesicle
Raised clear fluid-filled lesion < 0.5cm in diameter
Small blister
Define bulla
Raised clear fluid-filled lesion > 0.5cm in diameter
Large blister
Define pustule
Pus-containing lesion < 0.5cm in diameter
Define abscess
Localised accumulation of pus in the dermis or subcutaneous tissues
Define wheal
Transient raised lesion due to dermal oedema
Define boil
Staphylococcal infection around or within hair follicle
Define carbuncle
Staphylococcal infection of adjacent hair follicles
Multiple boils
Define excoriation
Loss of epidermis following trauma
Define lichenification
Well-defined roughening of skin with accentuation of skin markings
Define scales
Flakes of stratum corneum
Define crust
Rough surface consisting of dried serum, blood, bacteria and cellular debris that has exuded through eroded epidermis
Define scar
New fibrous tissue which occurs post-wound healing a- - atrophic = thinning
- hypertrophic = hyperproliferation within wound boundary
- keloidal = hyperproliferation beyond wound boundary
Define ulcer
Loss of epidermis and dermis
Define fissue
Epidermal crack often due to excess dryness
Define striae
Linear areas which progress from purple to pink to white
- histopathological appearance of a scar
What are striae a/w?
Excessive steroid usage
Glucocorticoid production
Growth spurts
Pregnancy
Define alopecia
Loss of hair
Define hirsutism
Androgen-dependent hair growth in a female
Define hypertrichosis
Non-androgen dependent pattern of excessive hair growth
Define clubbing
Loss of angle between posterior nail fold and nail plate
What is clubbing associated with?
Suppurative lung disease
Cyanotic heart disease
Inflammatory bowel disease
Idiopathic
Define koilonychia
Spoon-shaped depression of nail plate
What is koilonychia a/w?
Iron-deficiency anaemia
Congenital
Idiopathic
Define onycholysis
Seperation of distal end of nail plate from nail bed
What is onycholysis a/w?
Trauma
Psoriasis
Fungal nail infection
Hyperthyroidism
Define pitting
Punctate depression of nail plate
What is nail pitting a/w?
Psoriasis
Eczema
Alopecia areata
Define cellulitis
Spreading bacterial infection of skin
- involves deep subcutaneous tissue
Define erysipelas
Acute superficial form of cellulitis
- involves dermis and upper subcutaneous tissue
Causes of cellulitis
Streptococcus pyogenes
Staphylococcus aureus
Risk factors for cellulitis
Immunosuppression Wounds Leg ulcers Toeweb intertrigo Minor skin injury
Presentation of cellulitis
Most common in lower limbs Local signs of inflammation - tumor - rubor - calor - dolor Systemically unwell with fever, malaise or rigors
Management of cellulitis
Antibiotics - flucloxacillin or benzylpenicillin
Supportive care - rest, leg elevation, sterile dressings and analgessia
Complications of cellulitis
Local necrosis
Abscess
Septicaemia
Define staphylococcal scaled skin syndrome
Serious skin infection caused by staphylococcus aureus
Red blistering skin - looks like burn/scald
Causes of SSSS
Production of circulating epidermolytic toxin from phage group II, benzylpenicillin resistant (coagulase positive) staphylococci
Presentation of SSSS
Commonly seen in infancy and early childhood
Develops within few hours to few days
Worse over face, neck, axillae and groins
Scald-like appearance followed by large flaccid bulla
Perioral crusting
Intraepidermal blistering
Painful
Management of SSSS
Antibiotics - erythromycin
Analgesia
Cause of superficial fungal infections
Dermatophytes - tinea/ringworm
Yeasts - candidiasis, malassezia
Moulds - aspergillus
Define tinea corporis
Tinea infection of trunk and limbs
Itchy, circular or annular lesions with clearly define, raised and scaly edge
Define tinea cruris
Tinea infection of the groin and natal cleft
Define tinea pedis
Athlete’s foot
Moist scaling and fissuring in toewebs, spreading to sole and dorsal aspect of foot
Define tinea capitis
Scalp ringworm
Patches of broken hair, scaling and inflammation
Define candidiasis
Candidial skin infection
White plaques on mucosal areas, erythema with satellite lesions in flexures
Treatment of superficial fungal infections
Establish correct diagnosis - skin scrapings, hair or nail clippings or skin swabs
Treat know precipitating factors
Topical antifungal agents - terbinafine cream
Oral antifungal for severe - itraconazole
Avoid topical steriods
Describe squamous cell carcinoma
Locally invasive malignant tumour of epidermal keratinocytes or appendages
Potential to metastasise
Risk factors of squamous cell carcinoma
Excessive UV exposure
Pre-malignant skin conditions - actinic keratoses
Chronic inflammation - leg ulcers, wound scars
Immunosuppression
Genetic
Presentation of squamous cell carcinoma
Keratotic (scaly, crusty), ill-defined nodule which may ulcerate
Management of squamous cell carcinoma
Surgical excision
Mohs micrographic surgery - ill-defined, large, recurrent
Radiotherapy - large, non-resectable tumours
Describe malignant melanoma
Invasive tumour of epidermal melanocytes
Potential to metastasise
Risk factors for malignant melanoma
Excessive UV exposure - always burns never tans
History of multiple moles or atypical moles
FH
PH
Presentation of malignant melanoma
Asymmetrical shape Border irregularity Colour irregularity Diameter > 6mm Evolution of lesion Symptoms - bleeding, itching More common on legs in women and trunk in men
Types of malignant melanoma
Superficial spreading
- common on lower limbs, in young and middle age
- related to intermittent high-intensity UV exposure
Nodular melanoma
- common on trunk, in young and middle aged adults
- related to intermittent high-intensity UV exposure
Lentigo maligna melanoma
- common on face, in elderly population
- related to long-term cumulative UV exposure
Acral lentiginous melanoma
- common on palms, coles and nail beds, elderly population
- no clear relation to UV exposure
Management of malignant melanoma
Surgical excision - definitive treatment
Radiotherapy
Chemotherapy - metastatic disease
Functions of normal skin
Protective barrier against the environment Temperature regulation Sensation Vitamin D synthesis Immunosurveillance Appearance/cosmesis
Function of main cell types in the epidermis
Keratinocytes - produce keratin as a protective barrier
Langerhan’s cells - present antigens and activate T-lymphocytes for immune protection
Melanocytes - produce melanin - gives pigment to skin and protects cell nuclei from UV radiation induced DNA damage
Merkel cells - contain specialised nerve endings for sensation
Layes of the epidermis
Stratum basale - actively dividing cells - deepest layer
Stratum spinosum - differentiating cells
Stratum granulosum - cells lose nuclei and contain granules of keratohyaline - secrete lipids into intracellular spaces
Stratum corneum - layer of keratin - most superficial
Types of sweat glands
Eccrine - universally distributed
Apocrine - found in axillae, areolae, genitalia and anus
- function only from puberty onwards
Stages of wound healing
Haemostatsis
- vasocontriction and platelet aggregation
- clot formation
Inflammation
- vasodilation
- migration of neutrophils and macrophages
- phagocytosis of cellular debris and invading bacteria
Proliferation
- granulation tissue formation and angiogenesis
- re-epilelialisation
Remodelling
- collagen fibre re-organisation
- scar maturation
Define atopic eczema
Characterised by papules and vesicles on an erythematous base
Atopic eczema - most common
- usually develops by early childhood and resolves during teenage years
Causes of atopic eczema
Not fully understood
Commonly positive FH of atopy
Primary genetic defect in skin barrier function
Exacerbating factors of atopic eczema
Infections Allergens - chemicals, food, dust, pet fur Sweating Heat Severe stress
Presentation of atopic eczema
Commonly presents as itchy, erythematous dry scaly patches
More common on face and extensor aspects of limbs in infants and flexor aspects in children and adults
Acute lesions are erythematous, vestibular and weepy
Chronic scratching/rubbing can lead to excoriations and lichenification
Management of atopic eczema
General measures
- avoid exacerbating agens
- frequent emollients/bandages/bath oil or soap substitute
Topical therapies
- topical steriods for use in flare-ups
- topical immunomodulators as steriod sparing
Oral therapies
- antihistamines for symptomatic relief
- antibiotics for secondary bacterial infections
- antivirals for secondary herpes infections
Phototherapy and immunosuppressants for severe non-responsive cases
Complications of atopic eczema
Secondary bacterial infection - crusted weepy lesion
Secondary viral infection - pearly papules with central umbilications, viral warts
Define acne vulgaris
Inflammatory disease of the pilosebaceous follicle
Causes of acne vulgaris
Hormonal - androgen
Contributing factors of acne vulgaris
Increased sebum production
Abnormal follicular keratinization
Bacterial colonisation
Inflammation
Presentation of acne vulgaris
Mild acne - non-inflammatory lesions
- open and closed comedones (black and whiteheads)
Moderate and severe acne - inflammatory lesions
- papules, pustules, nodules and cysts
Commonly affects face, chest and upper back
Management of acne vulgaris
General measures - no specific food identified - treatment needs to be continues for at least 6 weeks to produce effect Topical therapies - benzoyl peroxide - topical antibiotics - topical retinoids Oral therapies - antibiotics - anti-androgens (female) Oral retinoids
Complications of acne vulgaris
Post-inflammatory hyperpigmentation
Scarring
Deformity
Psychological and social effects
Define psoriasis
Chronic inflammatory skin disease due to hyperproliferation of keratinocytes and inflammatory cell infiltration
Types of psoriasis
Chronic plaque - most common Guttate - raindrop lesions Seborrhoeic - naso-labial and retro-auricular Flexural - body folds Pustular - palmar-plantar ERythrodermic - total body redness
Causes of psoriasis
Complex interaction between genetic, immunological and enviromental factors
Precipitating causes of psoriasis
Trauma Infection - tonsillitis Drugs Stress Alcohol
Presentation of psoriasis
Well-demarcated erythematous scaly plaques
Lesions can be itchy, burning or painful
Common on extensor surfaces of body and over scalp
Auspitz sign - scratch and gentle removal of scales causes capillary bleeding
50% -> nail changes - pitting, onycholysis
5-8% -> psoriatic arthropathy
Management of psoriasis
General measures - avoid known precipitating factors - emolients to reduce scales Topical therapies - vitamin D analogues - corticosteriods - coal tar preparations - dithranol - retinoids - keratolytics - scalp preparations Phototherapy Oral - methotrexate - retinoids - ciclosporin - mycophenolate mofetil - fumaris acid esters - biological agents - infliximab
Complications of psoriasis
Erythroderma
Psychological and social effects
Causes of urticaria, angioedema and anaphylaxis
Idiopathic Food - nuts - sesame seeds - shellfish - dairy Drugs - penicillin - contrast media - NSAIDs - morphine - ACE-i Insect bites Contact - latex Viral or parasitic infections Autoimmune Hereditary
Describe urticaria
Due to local increase in permeability of capillaries and small venules
Large number of inflammatory mediators play a role but histamine derived from skin mast cells = major
Local mediator release from mast cells can be induced by immunological or non-immunological mechanisms
Presentation of urticaria
Swelling involving superficial dermis, raising dermis
Itchy wheals
Presentation of angioedema
Deeper swelling involving dermis and subcut tissues
Swelling of tongue and lips
Presentation of anaphylaxis
Bronchospasm
Facial and laryngeal oedema
Hypotension
Can initially present as urticaria and angioedema
Management of urticaria, angioedema and anaphylaxis
Antihistamines - urticaria
Corticosteroids - severe acute urticaria and angioedema
Adrenaline, corticosteriods and antihistamines for anaphylaxis
Complications of urticaria, angioedema and anaphylaxis
Urticaria is normally uncomplicated Angioedema and anaphylaxis can lead to - asphyxia - cardiac arrest - death
