Dermatology Flashcards
Describe toxic epidermal necrolysis
*Most commonly seen secondary to a drug reaction
*Covers >10% of the body surface area
*Systemically unwell: pyrexia and tachycardia
What is Nikolsky’s sign?
Epidermis separates with mild lateral pressure - Toxic epidermal necrolysis
Which drugs are known to induce TEN?
*Phenytoin
*Sulphonamides
*Allopurinol
*Penicillin
*Carbamezapines
*NSAIDs
What predicts mortality in toxic epidermal necrolysis
SCORTEN
What is the management of toxic epidermal necrolysis?
*Stop the precipitating factor
*Admit to ICU: special sheets and mattress, non-adherent dressing
*Volume loss and electrolyte derangement are potential complications - needs monitoring
*IV immunoglobulin 1st line, consider immunosuppressive agents e.g. cyclosporin
What are the complications of toxic epidermal necrolysis?
*Secondary infection: cellulitis and sepsis
*Permanent skin damage
*Visual complications
What is Erythema multiforme?
Hypersensitivity reaction most commonly triggered by infection, target lesions with mild pruritus
What are the features of erythema multiforme?
*Target lesions
*Initially seen on the back of hands/feet, spreads to torso
*Upper limbs more commonly affected than lower limbs
*Mild pruritis
*May be associated with a mild fever/stomatitis, muscle aches and joint aches, headaches or flu like symptoms
What are the causes of erythema multiforme?
*Viruses: herpes simplex
*Idiopathic
*Bacteria: mycoplasma, streptococcus
*Drugs: penicillin, sulphonamides, carbamezapine, allopurinol, NSAIDs, Oral contraceptive pill
*Connective tissue disease e.g. SLE
*Sarcoidosis
*Malignancy
What is the management of erythema multiforme?
*Look for underlying cause - if there is nothing from cultures consider CXR looking for mycoplasma pneumonia
*Normally resolves in 1-4 weeks but may be recurrent
*Severe cases: IV fluids, analgesia, steroids, antibiotics or antivirals if infection
What is acute urticaria?
*Hives caused by a histamine release by mast cells
*Raised itchy rash on the skin
What type of reaction is immune mediated urticaria?
Type 1 IgE
What are the causes of urticaria?
*Food/medication/animal allergy
*Contact with chemicals, latex or nettles
*Medication
*Viral infection
*Insect bites
What is the management of urticaria?
*High dose antihistamines: fexofenadine
*Oral steroids: prednisolone may be considered
*If severe: anti-leukotrienes e.g. montelukast or Omalizumab
What is erythroderma?
When over 95% of the body is covered by any type of rash
What are the causes of erythroderma?
*Eczema
*Psoriasis
*Drugs e.g. gold
*Lymphoma, leukaemia
*Idiopathic
What is the presentation of cellulitis?
*Erythema
* Warm or hot to the touch
*Tense/thick skin
*Oedematous
*Bullae
*If there is a golden crust this indicates staphylococcus aureus infection
What are the causes of cellulitis?
*Staphylococcus aureus
*Group A streptococcus e.g. strep pyogenes
*Group C streptococcus e.g. strep dysgalactiae
*MRSA
What is the ERON classification?
*Classifies the severity of cellulitis
*Class 1: no systemic symptoms or co morbidities
*Class 2: Systemic symptoms or co-morbidities
*Class 3: significant symptoms or co-morbidities
*Class 4: sepsis
What is the management of cellulitis?
*If ERON class 3 or 4, admit for IV antibiotics
*Flucloxacillin is usually first line
What is impetigo?
Superficial bacterial infection, usually caused by staphylococcus aureus, less commonly by streptococcus pyogenes, it is contagious
What is the difference between bullous and non bullous impetigo?
*Non bullous tends to occur around the nose and mouth, yellow crust
*Bullous forms 1-2cm fluid filled vesicles
How do you treat bullous impetigo?
Take swabs then give antibiotics, usually flucloxacillin
How do you treat non bullous impetigo?
- Topical fusidic acid, oral fluclox if widespread
*Give advice to not touch, not share cutlery or towels, avoid other people for 48hours following antibiotics or healed
What are the complications of impetigo?
*Cellulitis
*Scarring
*Sepsis
*Post strep glomerulonephritis
*Scarlet fever
Mild steroid
Hydrocortisone
Moderate steroid
Eumovate
Potent steroid
Betnovate
Very potent steroid
Dermovate
What are the symptoms of eczema herpeticum?
*Fever
*Lethargy
*Reduced oral intake
*Lymphadenopathy
*Erythematous rash, painful, sometimes itchy with vesicles and pus
What is the treatment of eczema herpeticum?
Aciclovir
What are the 4 types of leg ulcer?
*Venous
*Arterial
*Pressure
*Diabetic foot
Describe arterial ulcers
*Distal - affecting the dorsum of foot or toes
*Punched out, well defined
*Deep
*Painful
*Pain is worse on elevation and improved by lowering, worse at night as pt horizontal
*Pale colour due to poor blood supply
*Less likely to bleed
*Associated with PAD, absent pulses intermittent claudication, pallor
Describe venous ulcers
*Gaiter area - between top of foot and bottom of calf
*Associated with chronic changes e.g. venous eczema, hyperpigmentation
*More superficial and less painful
*Larger
*Increased likelihood of bleeding
*Irregular border
*Pain relieved by elevation, worse on lowering
What is the treatment of venous ulcers?
*Compression therapy
*Analgesia
*Refer to nursing for cleaning, debridement and dressing
*Refer to dermatology, pain clinic if required
What investigations should be carried out for leg ulcers?
*ABPI to assess for arterial disease
*FBC and CRP looking for infection, anaemia or malnutrition
*Skin biopsy if suspected cancer
*Charcoal swab if infection is suspected
What is psoriasis?
Chronic, relapsing and remitting skin disease
What are the peak age onsets of psoriasis?
*20-30
* 50-60
What are the types of psoriasis?
*Plaque: plaques with silver scales
*Pustular: pustules form under erythematous skin- can be systemically unwell
*Guttate: small raised papules, often triggered by a streptococcal throat infection, resolves in 3-4 months
*Erythrodermic: extensive erythematous inflamed areas - skin comes away in large patches
*Inverse/flexural
*Palmar/plantar
What is the management of psoriasis?
- Topical creams and ointments
*Phototherapy light treatments
*Systemic therapies/immunosuppression: methotrexate, acitretin, dimethyl fumerate
What are the associations of psoriasis?
*Nail psoriasis: pitting, thickening, onycholysis, ridging, discolouration
*Psoriatic arthritis
*Psychosocial: self esteem/mood
What are the features of rosacea?
*Flushing
*Telangiectasia
*Persistent erythema
*Rhinophyma
*Blepharitis if ocular involvement
What is the management of roseca?
*Topical metronidazole for mild symptoms
*Topical brimonidine gel if predominantl flushing and limited telangiectasia
What is pemphigus vulgaris?
*Autoimmune condition against desmoglein 3
*Mucosal ulceration, Emily ruptured skin blisters
*painful but not itchy
What is the treatment of pemphigus vulgaris?
Steroids
What is bullous pemphigoid?
*Autoimmune against hemidesmosomal proteins
*Itchy, tense blisters, typically around the flexures, heal without scar
*Usually mouth is spared- no mucosal involvement
What is the management of bullous pemphigoid?
Oral steroids, immunosuppressants
What are the types of skin cancer?
- basal cell carcinoma
- squamous cell carcinoma
- malignant melanoma
What is the most common skin cancer?
Basal cell
What are the types of basal cell carcinoma?
- nodular
- superficial
- pigmented
- morphoeic/sclerotic
Describe a nodular basal cell carcinoma
- nodule >0.5cm raised lesion
- shiny ‘pearly’
- telangectasia/blood vessels
- often centrally ulcerated
Management of basal cell carcinoma
surgical excision 3-4mm margin
What are the premalignant forms of squamous cell carcinoma?
- actinic keratoses
- bowen’s disease
What is the appearance of a squamous cell carcinoma?
keratinisation, nodule
What is the management of a squamous cell carcinoma?
Surgical excision 4mm margin
What is the management of a pre-malignant squamous cell carcinoma?
- topical imiquimod/ 5-fluorouracil cream
- cryotherapy
- photodynamic therapy
What are the main diagnostic features for malignant melanoma?
- cahnge in size
- change in shape
- change in colour
What is alopecia areata?
Hair loss thought to be autoimmune. Hair will regrow in 50% by 1 year and 80-90% eventually
What is acanthosis nigracans?
symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin
What are the causes of acanthosis nigracans?
- type 2 diabetes
- GI cancer
- Obesity
- Cushings
- PCOS
- hypothyroidism
- acromegaly
- familial
- oral contraceptive, nicotinic acid
What is erythema nodosum?
Tender, erythematous, nodular lesions. Usually over the shins
What are the causes of erythema nodosum?
- Infection: streptocci, TB
- Systemic disease: Sarcoidosis, IBD
- Malignancy, lymphoma
- Drugs: penicillin, sulphonamides, OCP
- pregnancy
What are the causes of pyoderma gangrenosum?
- idiopathic
- IBD
- Rheumatoid arthritis, SLE
- Haem: lymphoma, myeloid leukaemia, myeloproliferative disorders
- Granulomatosis with polyangiitis
Describe pyoderma gangrenosum
- typically on the lower limb
- starts as a small pustule, red bump or blood blister
- skin breaks down resulting in an ulcer which may be deep and necrotic
Describe pretibial myxoedema
- symmetrical, erythemaotus lesions
- shiny orange peel skin
Describe necrolibosis lipodica diabeticorum
- shiny, painless areas of yellow/red skin, typically on the shin of diabetics
- often associated with telangiectasia
Dermatitis hepatiformis
- itchy skin lesions on the extensor surfaces
- associated with coeliac
- Ig A deposition
What skin condition is associated with coeliac disease?
Dermatitis hepatiformis
Erythema ab igne
Over exposure to infrared
Erythema multiforme
Target lesions initially on the back of hands/feet then torso
What infections cause erythema multiforme?
- HSV
- mycoplasma
- streptococcus
What are the systemic causes of erythema multiforme?
- SLE
- Sarcoidosis
- malignancy
What drugs cause erythema multiforme?
- penicillin
- sulphonamides
- allopurinol
- carbamazepine
- NSAIDs
- OCP
Treatment for keloid
Intra lesional steroids
What is lichen planus
- itchy papular rash
- palms, soles, genitalia, flexor surfaces of arms
- white lacy pattern on buccal mucosa
- koebner phenomenon may be seen
What is the management for lichen planus?
Topical steroids
