Dermatology Flashcards
Cellulitis and erysipelas
Cellulitis
- acute infection of skin and soft tissues (deep)
- from B-haemolytic streps and staphs (strep pyogenes or staph aureus
- deep, less well defined
- pain, swelling, erythema, warmth, systemic upset, lymphadenopathy
- risk factors - previous cellulitis (damaged lymph drainage), broken skin (trauma, dermatitis, tinea), diabetes
- complications - necrotising fasciitis, abscess, sepsis
- treat with elevation, benzylpenicillin IV + flucloxacillin PO (or erythromycin)
- as opposed to erysipelas - more superficial in dermis and upper subcutaneous, well defined, raised border, caused by Strep pyogenes
Impetigo
- well-defined red patches with honey coloured crust
- superficial infection, usually from Staph aureus
Herpes simplex
- viral infection
- recurrent, often preceded by burning/itching
- coalescing polygonal vesicles, then crusting, heal without scarring
- can be very severe if infection in patient with atopic dermatitis (eczema)
- type 1 non-genital, type 2 genital
- no treatment usually if oral, but if genital then oral aciclovir, hygiene measures and abstinence
Herpes zoster
- from varicella-zoster virus
- virus becomes dormant in dorsal root ganglia after chickenpox infection, then recurs in dermatomes
- pain and malaise may precede rash
- then polymorphic red papules, vesicle, pustules
- use antiviral aciclovir if >50yo, ophthalmic involvement, severe or immunosuppressed WITHIN 72hrs onset
- need specialist advice if pregnant, immunocompromised or ophthalmic
- can be vaccine, can use immune globulin post-exposure
Necrotising fasciitis
- surgical emergency! (go to surgeons not dermatologists)
- bacterial infection of deeper tissues, due to toxins liquifying tissues and coagulating blood
- strep, which have toxins – digest collagen, elastase etc, clot blood – streptokinase
Symptoms
- PAIN (out of proportion to what is visible on the surface)
- unwell systemically, -> sepsis
- mottled skin, progresses to dark haemorrhagic and necrotic skin with bullae
- crepitus (gas under the skin)
- anaesthetic (loss of sensation) – late sign – when nerve endings liquified
Imaging (shouldn’t be time, need operation)
- MRI will detect but too long (incidental)
- Xray may show necrotic tissue and gas if unsure
Diagnosis
- finger test (liquified tissue)
- lack of bleeding
- dishwater leakage
Treatment
- admit, refer to surgeons – needs urgent debridement or will spread
- swabs and blood cultures
- broad spectrum abx
- sepsis management (25% mortality)
Scabies
- highly contagious infestation of mites
- common, especially in children and young adults
- direct person-person spread
- see short line on surface of skin where mite digs burrow, then itch and red rash in response to eggs lain
- very itchy papules, vesicles, pustules, nodules (affecting esp finger-webs, wrist flexures, axillae, abdomen, groins
- excoriated and eczematized commonly
Treatment
- all members of household and close contacts at the same time
- permethrin cream or malathion to all body parts, leave 24hrs, oral if severe
- bathe and scrub all skin, wash all sheets/towels/clothing
Tinea
= ringworm, fungal infection dermatophytes
- direct spread
- round, scaly, itchy lesion with edge more inflamed than centre
- tinea pedis foot, capitis scalp, cruris groin, corporis body, unguium nail etc
Management
- send skin scraping for microscopy and culture
- topical antifungal terbinafine or imidazole
Candida
- yeast, usually commensal of mouth and GI tract
- can infect mouth, vagina, glans of penis
- pink and moist lesions
- treat with imidazole creams on skin/vagina
Viral warts
- caused by HPV in keratinocytes
- warts and verrucae at sites of trauma (fingers, elbows, knees, soles of feet)
- can coalesce into confluent lesions, mosaic warts
- contagious but low risk transmission
- usually disappear few months-2 years, but can treat if painful, distressing or persistent
- topical salicylic acid, cryotherapy
- genital warts sexually transmitted, resolve in 6mo, screen for other STIs
Acne
= disorder of pilosebaceous units
- seborrhoea = greasy skin, then hyperkeratosis in duct forms microcomedones, then colonisation with Propionibacterium acnes and inflammatory reaction
- mainly affects face, chest and back
- family history of acne, or endocrine problems
- likely various treatments tried before presentation at primary care, beware psychological effect
- advise no effect of hygiene, not infectious, diet no effect - not your fault!
OE:
- open comedones = blackheads
- closed comedones = whiteheads
- papules, pustules
- nodular cystic lesions
- scarring (be alert to aggressive treatment, as scars likely permanent - atrophic ‘ice-pick’ or hypertrophic keloid)
Classification and treatment of mild/moderate/severe acne
MILD
- mainly facial comedones
- topical benzoyl peroxide (start low %) or topical retinoid (not in pregnancy) or topical antibiotic
- need 8 weeks for effectiveness
MODERATE
- inflammatory lesions dominate, affecting face ± torso
- topical antibiotic combined with benzoyl perioxide or topical retinoid for max 12 weeks
- oral antibiotic eg tetracycline/doxycycline for 4-6 months with topical BP
- consider standard COCP or dianette (has antiandrogen activity)
SEVERE
- nodules, cysts, scars, inflammatory papules and pustules
- refer to specialist
- isotretinoin (very effective but teratogenic, maybe psychiatric effects, skin dryness)
Rosacea
- common, 30s+, more in women
- chronic relapsing remitting disorder of blood vessels and pilosebaceous units in centre of face
- typically in fair-skinned
- pre-features of flushing from stress/embarrassment, alcohol, spices
- central symmetrical facial rash with erythema, teleangiectasia, papules and pustules (no comedones), inflammatory nodules
- ophthalmic involvement eg dry eyes, irritation, redness, crusting
- treat with soap substitutes, avoid sun overexposure
- mild - metronidzole gel
- moderate-severe - oral tetracycline for 4 months
Bullous pemphigoid and pemphigus
Bullous pemphigoid
- autoimmune blistering, mainly in elderly, relapsing remitting
- tense blisters
- immunofluorescence on skin biopsy
- need potent topical steroids PO
Pemphigus
- in younger people
- flaccid superficial blisters, rupture leaving widespread erosions
- oral mucosa often
- treat with PO prednisolone
Atopic eczema
- rash with inflamed red skin, poorly demarcated, easily irritate, itchy and associated excoriations
- family or personal hx of atopy common, allergy associated
- can get infection from staph (weeping, crusting or pustules), or lichenification from chronic rubbish
- most remission by age 13
Diagnosis
- itchy skin, +
- onset before age 2
- past or current flexural involvement
- atopy in self or family
- beware eczema herpeticum (severe weeping rash from herpes infection, may be fatal)
Treatment of eczema
About control not cure.
- emollients used liberally to treat dryness and act as barrier, + soap substitutes
- topical steroids - for exacerbations, only on active skin, OD after emollient. Use the weakest effective (but advise safe!) - should be <1 week if acute flare or 4-6 weeks for control in chronic disease
- maybe antihistamine eg hydroxyzine at night to reduce itch/scratch cycle
Eczema herpeticum
- widespread viral infection, usually HSV1 or 2
- clusters of itchy painful blisters, maybe umbilicated early
- background of chronic skin condition, eg atopic eczema
- early systemic illness
- may become secondary bacterial infection
- needs swab for viral PCR and bacteriology
Complications
- encephalitis, hepatitis, pneumonitis, corneal ulceration, if over the eye
Treatment
- oral acyclovir (if adults and well), or IV if children/unwell
- antibiotics for secondary infection
- refer to ophthalmology
- topical steroids ? – maybe needed if eczema is out of control
Erythroderma
= exfoliative dermatitis, intense widespread inflammation of the skin (>90% body surface)
- in response to drugs eg sulfonamides, allopurinol, carbamazepine
- 70% have pre-existing skin conditions eg eczema, psoriasis,
Clues to cause
- ooze – eczema
- pustules – psoriasis
Complications
- oedema (albumin loss from leakage)
- hypothermia, dehydration
- infection
Need to discontinue meds, supportive care, bland emollients, mild topical steroid
Psoriasis
- two peaks of onset, in 20-30s, then 60s
- chronic inflammatory with scaly erythmatous plaques, well demarcated erythematous plaques, topped by silvery scale
- relapsing remitting course, triggers from stress, infections, skin trauma, drugs, alcohol, obesity, smoking, climate
- inherited susceptibility
- usually affecting elbows, knees, sacrum, scalp
- also signs in joints (7%, seronegative arthropathy) and nails (50%)
Treatment for control not cure
- consider phototherapy or systemic therapy if >10% body area
- emollients to reduce scale and ease itch
- topical steroid OD + topical vitamin D preparation for 4 weeks or until clear
Emollients
1st line to treat eczema and psoriasis
- stops water loss (traps moisture), needs a thin film of grease all the time
- spectrum of greasiness - pure paraffin is greasiest, but flammability risk, need to change clothing regularly, beware smokers, and beware slips and trips. Zeroderm, epaderm, white soft paraffin/liquid paraffin 50:50, emollin spray, emulsifying ointment.
- creams = ointment + water + extras
- lotion is more watery so maybe less effective (but maybe preferred) – cetraben cream, isomel gel, E45 lotion
Suggest 500ml bottle per week, application 3-4x a day (not realistic as outpatient!)
Patient choice key - the treatment effective is the one used
- always apply in the direction of hair growth (or risk additional folliculitis)
Topical corticosteroids
- different strengths according to severity of condition and the area of the body treated – especially cautious with faces and flexures
- apply thinly, as risk of skin atrophy, depigmentation, acne-like eruption, contact allergy – in reality is rare unless strong steroid used lifelong! As many problems from underuse than overuse.
- also consider base (lotion, ointment etc), and may add eg bacteriocidal agent (betnovate C) or something to break down scale such as salicylic acid (diprosalic) for eg soles of feet eczema etc. Probably will put steroid on underneath.
Ladder of strength
- Mild – Hydrocortisone 1%, Timodine
- Moderate – Clobetasone butyrate (eumovate), Alcometasone diproprionate (modrasone), Trimovate
- Potent – Betamethasone valerate (betnovate), Hydrocortisone butyrate (locoid), Mometasone furoate (elocon)
- Very potent – Clobestasol proprionate (dermovate)
Go up a rung of a ladder by wrapping in plastic dressing! First decide if appropriate to wrap, and then adjust steroid strength accordingly
Treatment of psoriasis
1) Potent corticosteroid OD + vitamin D analogue (calcipotriol) OD for 4-8 weeks
2) Vitamin D analogue BD (no steroid) 8-12 weeks
3) Potent topical steroid BD and coal tar prep (exorex lotion) OD or BD
4) Refer to secondary care! Can try diathranol ointment, phototherapy, methotrexate, biologic drugs
Urticaria
Ordinary:
- acute - smooth erythematous itchy hives and wheals precipitated by infections, parasites, chemicals, systemic disease
- chronic - idiopathic, can last months-years
Physical:
- induced by external trigger eg cold contact, delayed pressure
Urticarial vasculitis:
- cutaneous lesions looks like urticaria (tender wheals), maybe associated with SLE
Cutaneous signs of systemic disease
Diabetes - flexural candidiasis, necrobiosis lipoidica, acanthosis nigricans, folliculitis
Coeliac disease - dermatitis herpetiformis (itchy burning blisters on elbows, ankles, scalp)
Inflammatory bowel disease - erythema nodosum eg on shins
SLE - facial butterfly rash, photosensitivity, alopecia
Erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis
Erythema multiforme - hypersensitivity after eg herpes simplex or drug reaction, get target lesions, self-resolves in 3 weeks
Stevens-Johnson syndrome
- rare drug reaction, 40% to abx, anticonvulsants, allopurinol
- vague URTI symptoms 2-3 weeks after starting drug, then rash affecting <10% body surface area
- painful erythematous macules from target lesions, severe mucosal ulceration including conjunctivae, oral cavity, labia, urethra
Toxic epidermal necrolysis
- flu-like symptoms, then skin involvement affecting >30% body surface
- widespread dusky erythema, then necrosis of large sheets of epidermis
- mortality 30%
- nikolsky sign – skin peels away near the blister with lateral traction, even through it looks normal, as there is full thickness involvement of epidermis
- manage in ITU or burns unit, supportive care, avoid debridement
Diagnosis
- biopsy to confirm, exclude SSSS (staphylococcal scalded skin) or other bullous disease
Lipodermatosclerosis
- usually bilateral
- acutely may be mistaken for cellulitis
- chronically – woody firm texture, red shiny skin, ‘inverted champagne bottle legs’
- increased hydrostatic pressure in veins causes endothelial cell damage and release of pro-inflammatory mediators, release of MMPs
Melasma
= chloasma
Smooth brown (hyperpigmented) patches, especially on face
- related to pregnancy or oral contraceptive use
Vitiligo
Smooth white (hypopigmented) patches or macules, symmetrical
- associated with autoimmunity, esp thyroid disease
- melanocyte defect drives autoimmune melanocyte destruction
- need sun protection
Actinic (solar) keratoses
- pre-malignant, common from SUN
- crumbly yellow-white scaly crusts on sun-exposed skin
- may regress or recur, rarely progress to SCC
Treatment
- none, or emollient, if mild
- diclofenac gel
- fluorouracil cream
- imiquimod cream
- cryotherapy
- photodynamic therapy
- surgical excision only if atypical and unresponsive to treatment
Bowen’s disease
= SCC in situ
- well-defined slow growing red scaly plaque with flat edge
~5% progress to SCC, but high risk metastasis after
- from SUN, radiation, immunosuppression, HPV infection
- treat with cryotherapy, topical fluorouracil, phototherapy, cutterage, excision
Basal cell carcinoma
- commonest skin cancer
- tend to be 12-18 months until presentation, slow growing and subtle
Appearance
- usually nodular, pearly grey with rolled telangiectatic edge ± central ulcer
- on face or sun exposed site
- no mets, but slowly causes local destruction if untreated
- can also be superficial red scaly plaque with raised smooth edge, often trunk or shoulders
- caused by SUN and immunosuppression
- treatment depends on type, site, if recurrent, but usually excision (complete, Mohs or tissue sparing). If no, cryotherapy, cutterage, radiotherapy, phototherapy, topical imiquimod or fluorouracil for superficial
Seborrhoeic keratoses
- benign greasy-brown warty lesions
- usually on back, chest and face
- common in elderly
Benign melanocytic naevi
= common mole
Congenital
- present at birth
- if >20cm risk for malignancy
Acquired melanocytic naevi
- start in childhood-young adults
- start as flat evenly pigmented, then become raised evenly pigmented dome-shaped, then pale brown papules, then disappear in old age
Malignant melanoma
- 5th commonest cancer in the UK, common in <50s, high mortality
- 2WW referral for any pigmented lesion of concern
- Breslow thickness determines mortalaity
Risk factors
- SUN - UV exposure and significant sunburns
- fair complexion
- many melanocytic or dysplastic naevi
- family history
- previous melanoma
- old age
ABCDEF(EFG) to identify Asymmetrical outline Border irregularity or blurring Colour variation (esp beware blue) Diameter >6mm Evolution (changing mole) Funny looking (looks different from others) Elevated Firm Growing
Malignant melanoma
- 5th commonest cancer in the UK, common in <50s, high mortality
- 2WW referral for any pigmented lesion of concern
- prescribe vitamin D!
- needs wide local excision, then if - Breslow thickness >4mm CT to stage, and maybe sentinel node biopsy
Risk factors
- SUN - UV exposure and significant sunburns
- fair complexion
- many melanocytic or dysplastic naevi
- family history
- previous melanoma
- old age
ABCDEF(EFG) to identify Asymmetrical outline Border irregularity or blurring Colour variation (esp beware blue) Diameter >6mm Evolution (changing mole) Funny looking (looks different from others) Elevated Firm Growing
Types of melanoma
Superficial spreading (70%)
- slowly enlarging pigmented lesion with colour variation and irregular border
- common on trunks or men or legs of women
Nodular (15%)
- most aggressive and rapid, invade deeply and metastasise quickly
- often darkly pigmented but may be amelanotic
Types of melanoma
Superficial spreading (70%)
- slowly enlarging pigmented lesion with colour variation and irregular border
- common on trunks or men or legs of women
Nodular (15%)
- most aggressive and rapid, invade deeply and metastasise quickly
- often darkly pigmented but may be amelanotic
Acral lentiginous (10%)
- on palms, soles, and under nails (pigmented line under nail)
- most common type in black and asian skin
All need wide local excision (2mm margin normal skin around + cuff subcut fat)
Alopecia
Non-scarring
- causes may be reversible - stress, nutritional deficiency, androgenic
- alopecia acreta - smooth well-defined hair loss, spontaneous regrowth in 3 months usually
- or totalis/universalis
- difficult treatment, topical or intralesional steroids, psychological support
Scarring
- irreversible loss
- where inflammatory disease damages follicular stem cells, or follicles damaged by trauma or tumour
Primary lesions definitions
Macule – a flat area of altered colour, eg freckles
Patch – larger flat area of altered colour or texture
Papule – solid raised lesion < 0.5cm in diameter
Pustule – pus-containing lesion <0.5cm in diameter
Nodule – solid raised lesion >0.5cm in diameter with a deeper component
Bulla – large blister, raised, clear fluid-filled lesion >0.5cm in diameter
Vesicle – small blister, raised, clear fluid-filled lesion <0.5cm in diameter
Wheal – transient raised lesion due to dermal oedema
Abscess – localised accumulation of pus in the dermis or subcutaneous tissues
Boil/furuncle – Staphylococcal infection around or within a hair follicle
Carbuncle – Staphylococcal infection of adjacent hair follicles (multiple boils/furuncles)
Plaque – palpable scaling raised lesion >0.5cm in diameter
Dermatology presentations by age
Babies/infants
- haemangioma, congenital naevi, skin manifestations of inherited disorders, eczema
Children
- infections, eczema, benign skin tumours
Adolescents
- acne, guttate psoriasis, seborrhoeic dermatitis, benign skin tumours
Early adulthood
- psoriasis, seborrhoeic dermatitis
Older adults
- rosacea, varicose eczema/ulceration, skin cancers
Elderly
- skin cancers, psoriasis, senile pruritis, bullous pemphigoid, shingles, asteatotic eczema, varicose eczema
