Dermatology Flashcards
Eczema
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Differentials
Risk Factors
Treatment
Definition - defects in the skin barrier causing inflammation and irritation
Epidemiology - 1/10 people across their lifetime
Pathogenesis - family history, gaps in the skin barrier allow irritants to enter
Presentation - erythema, scaling, vesicles/papules, kerosis
Investigations - IgE levels, allergy testing, oral food challenge
Differentials - seborrhoea dermatitis, contact dermatitis
Risk Factors - Irritants, allergens
Treatment - emollients, topical steroid for flares
Mild: hydrocortisone
Moderate: eumovate
Potent: betnovate
Very Potent: dermuvate
Herpeticum: IV acyclovir
Topical calcineurin inhibitors
Psoriasis
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Risk Factors
Treatment
Definition - chronic inflammation skin disease due to hyper proliferation ion keritocytes and inflammatory cell infiltration
Epidemiology - 2% of population, early adulthood and 50-60
Pathogenesis - T lymphocyte driven disorder, upregulation of Th1 types T cell cytokines
Presentation -
Plaque - common on extensor surfaces
Guttate - small tear drop plaques on trunk after strep infections - common in children
Pustular - pustules on palms and soles - EMERGENCY
Erythrodermic - serious erythroderma and systemic illness
Investigations - Silvery plaques on examination
Auspitz sign - bleeding when scraped
Koetner phenomenon - psoriasis after trauma
Risk Factors - polygenic, environmental triggers: UV light, increased alcohol, stress, strep A
Treatment - emollients, topical vitamin D analogues, calcitriol cream, phototherapy, DMARD
Acne Vulgaris
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Treatment
Definition - chronic inflammation of neosebaceous units of the skin
Epidemiology - teenage years
Pathogenesis - increased sebum production and trapping of keratin
Presentation -
White heads: closed comedones
Black heads: open comedones
Papules: small red bumps
Pustules: white/yellow spots
Nodules: large red bumps
Investigations - swabs
Treatment -
Mild: benzyl peroxide
Topical antibiotics: clindamycin/erythromycin
Topical Retinoids: tazarotene gel
Severe: oral tetracyclines - doxycycline then minocycline
Hormonal Treatment: oral co-cyprindiol
Rosacea
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Treatment
Definition - chronic flushing of forehead, nose, cheeks, chin
Epidemiology - female, pale skin tones
Pathogenesis - telangiectasia: superficial blood vessels
Presentation - exacerbated by: sun, hot weather, warm baths, stress, spicy foods
Investigations - dermatological examination
Treatment - sun protection, topical; azelaic acid, metronidazole, laser therapy
Erythrodema
Definition
Pathogenesis
Presentation
Investigations
Treatment
EMERGENCY
Definition - widespread erythema affecting 90% of skin
Pathogenesis - dermatitis: atopic/seborrhoeic/ contact psoriasis
Presentation - erythema across 90% of body
Investigations - dermatological examination
Treatment - support for emergent condition, fluids, emollients, treatment of underlying disease
Steven Johnson Syndrome - toxic epidermal necrolysis
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Treatment
EMERGENCY
Definition - type 4 hypersensitivity disorder, skin detachment with mucocutaneous complications
Epidemiology - reaction to medications
Pathogenesis - medication reactions: penicillin, sulphonamides, lamotrigine, carbamazepine, phenytoin, allopurinol, NSAIDs, COCP
Infection - mycoplasma pneumonia
Presentation - fever, itching, erythema, purple/red skin rash/blisters, skin shedding leaving raw tissue
Investigations - nikolsky sky: rubbing = skin shedding, FBC, cultures
Treatment - supportive: antiseptics, analgesia, ophthalmic care, steroids and immunosuppressants
Melanoma
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Differentials
Risk Factors
Treatment
Definition - malignant cancer of melanocytes
Epidemiology - most common skin cancer, younger people
Pathogenesis - ABCDE for diagnosis
A - asymmetrical shape
B - border irregularity
C - colour irregularity
D - diameter>6mm
E - elevation/evolution
Presentation
Investigations biopsy, staging
Differentials - benign pigmented naveous, seborrhoea wart, pyogenic granuloma
Risk Factors - UV exposure, red hair, skin type 1, atypical moles
Treatment - surgical excision, removal of regional lymph nodes, metastases common: liver, lung, CNS
Adjuvant chemo/immunotherapy
Basal Cell Carcinoma
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Risk Factors
Treatment
Definition - locally invasive tumour of epidermal keratinocytes
Epidemiology - elderly on head/neck
Pathogenesis -
Presentation - small pink/skin coloured nodule, central depression, pearly rolled edges, surface telangiectasia, slowly enlarging
Investigations - biopsy and staging
Risk Factors type 1+2 skin, frequent sunburn, outdoor occupation, ageing, male
Treatment - surgical excised with wide borders and histology, cryotherapy, photodynamic therapy, radiotherapy
Squamous Cell Carcinoma
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Risk Factors
Treatment
Definition - locally invasive malignant tumour of epidermal keratinocytes
Epidemiology - older people, sun exposed sites
Pathogenesis -
Presentation - lesions are kertaotic, ill defined nodules that may ulcerate, rapid growth
Investigations - regional lymph node examination
Risk Factors - type 1/2 skin, frequent sunburn, outdoor occupation, smoking
Treatment - surgical excision with minimal margin on 5mm, radiotherapy especially if non resectable
Vitiligo
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Differentials
Risk Factors
Treatment
Definition - autoimmune disease: loss of melanocytes = loss of pigmentation
Epidemiology - genetic component
Pathogenesis - Segmental: children, rapid onset, no other autoimmune disease
Non-segmental: adults, progressive with noticeable flares, other autoimmune disease
Presentation - well demarcated smooth flat patches of depigmentation, white body hairs in affected areas
Investigations - wood’s lamp examination, biopsy
Differentials - piebaldism, waardenburg’s syndrome, tuberous sclerosis
Risk Factors - age<30, family history, autoimmune disease
Treatment - autoimmune screening, sunscreen use, topical steroid induced pigmentation
Alopecia Areata
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Differentials
Risk Factors
Treatment
Definition - autoimmune disease, destruction of hair follicles - patches of hair loss
Epidemiology - Fx
Pathogenesis -
Presentation - bald spots on scalp, surrounding exclamation, childhood onset
Investigations - examination, positive hair pull test
Differentials - trichotillomania, tines capitis, telogen effluvium
Risk Factors - autoimmune disease, fx
Treatment - reverses spontaneously, can be permentant, steroid injections to induce regrowth
Dermatomyositis
Definition
Presentation
Investigations
Differentials
Risk Factors
Treatment
Definition - autoimmune disease, inflammation in the skin and muscles
Presentation - heliotrope rash, gottron’s papules (red papules on dorsal finger joints), photosensitivity, nail fold capillary dilatation
Investigations - serum creatinine kinase, serum aldolase, electromyogram (EMG), muscle biopsy
Differentials - SLE, psoriasis, T cell lymphoma
Risk Factors - ILD association, genetic predisposition, female, black
Treatment - oral corticosteroids, physiotherapy
Cellulitis
Definition
Pathogenesis
Presentation
Investigations
Risk Factors
Treatment
Definition - infection of deep dermis and subcutaneous tissue
Pathogenesis - streptococcus progenies and staph aureus
Presentation - LL, erythema, pain, swelling, fever, sepsis
Investigations - FBC, ESR, CRP, U+E, skin swab, skin aspirate, biopsy
Risk Factors - diabetes, venous insufficiency, eczema, oedema and lymphoedema
Treatment - flucloxacillin, severe = co-amoxiclav
Impetigo
Definition
Epidemiology
Pathogenesis
Presentation
Investigations
Differentials
Risk Factors
Treatment
Definition - highly contagious and common bacterial infection
Epidemiology - children
Pathogenesis - staphylococci or streptococci
Presentation - face, flexors, limbs, golden crusted skin lesions around mouth, very contagious
Investigations bacterial skin culture
Differentials - herpes simplex, varicella, dermatophytosis
Risk Factors - increase humidity, malnutrition, poor hygiene, over crowding
Treatment - hydrogen peroxide 1% cream, topical fusidic acid
Extensive = flucloxacillin
School exclusion until crusted/48 hours of antibiotics
