DERM Flashcards
Define Basal Cell Carcinoma
Commonest form of skin malignancy, also known as a rodent ulcer
Aetiology/ Risk factors of basal cell carcinoma
• MAIN RISK FACTOR: prolonged sun exposure or UV radiation • Seen in Gorlin's syndrome • Other risk factors: o Photosensitising pitch o Tar o Arsenic
Epidemiology of basal cell carcinoma
- COMMON in those with FAIR SKIN
- Common in areas of high sunlight exposure
- Common in the elderly
- Rare before the age of 40 yrs
- Lifetime risk in Caucasians = 1 in 3
Presenting symptoms of basal cell carcinoma
- A chronic slowly progressive skin lesion
- Usually found on the:
o FACE o Scalp o Ears o Trunk
Recognise the signs of basal cell carcinoma on physical examination
• NoduloJulcerative (MOST COMMON)
o Small glistening translucent skin over a coloured
papule
o Slowly enlarges
o Central ulcer with raised pearly edges
o Fine telangiectasia over the tumour surface
o Cystic change in larger lesions
• Morphoeic
o Expanding
o Yellow/white waxy plaque with an illMdefined edge
o More aggressive than nodulo-ulcerative
• Superficial
o Most often on trunk
o Multiple pink/brown scaly plaques with a fine edge expanding slowly
• Pigmented
o Specks of brown or black pigment may be present in any BCC
Investigations for basal cell carcinoma
- Biopsy is RARELY necessary
* Diagnosis is mainly on clinical suspicion
Define Contact Dermatitis
An inflammatory skin reaction in response to an external stimulus, acting either as an allergen or an irritant
Aetiology/ Risk Factors of contact dermatitis
• There are TWO main types of contact dermatitis that may coMexist:
o ALLERGIC - a delayed type IV hypersensitivity reaction, which occurs after
sensitisation and subsequent re-exposure to the allergen
o IRRITANT - an inflammatory response that occurs after damage to the skin,
usually by chemicals
• Common ALLERGENS
o Cosmetics (e.g. fragrances) o Metals
o Topical medications
o Textiles
• Common IRRITANTS
o Detergents and soaps
o Solvents
o Powders
Epidemiology of contact dermatitis
- 4-7% of all dermatology consultations
* Hands are most commonly affected
Presenting symptoms and signs of contact dermatitis
- HANDS are the most frequently affected
- Contact dermatitis from clothing can occur in the axillae, groins and feet
- Redness of skin
- Vesicles and papules in the affected area
- Crusting and scaling of skin
- Itching of an affected area
- Fissures
- Hyperpigmentation
- Pain or burning sensation
- Make sure you do a thorough OCCUPATIONAL HISTORY
Investigations for contact dermatitis
- NO investigations necessary most of the time
* Some may need patch testing
Define Eczema
A pruritic papulovesicular skin reaction to endogenous and exogenous agents
Aetiology/ Risk Factors of eczema
• There are lots of types because there are many different triggers
• Exogenous
o Irritants (e.g. nappy rash)
o Contact (delayed type 4 hypersensitivity reaction to an allergen)
o Atopic
• Endogenous
o Atopic
o Seborrhoeic
o Pompholyx (a type of eczema that affects the hands and feet) o Varicose
o Lichen simplex
• Varicose - due to increased venous pressure in lower limbs
Epidemiology of eczema
- Contact - prevalence: 4%
- Atopic - onset in first year of life, childhood incidence: 10-20%
Recognise the presenting symptoms of eczema
- Itching
- Heat
- Tenderness
- Redness
- Weeping
- Crusting
- Ask about occupational exposure to irritants (eg.. Bleach)
- Ask about personal/family history of atopy (e.g. asthma, hay fever)
Signs of eczema on physical examination
• Acute
o Poorly demarcated erythematous oedematous dry scaling patches
o Papules
o Vesicles with exudation and crusting
o Excoriation marks
• Chronic
o Thickened epidermis
o Skin lichenification
o Fissures
o Change in pigmentation
• Based on type of eczema
o Atopic - mainly affects face and flexures
o Seborrhoeic - yellow greasy scales on erythematous plaques. Commonly found
on eyebrows, scalp, presternal area
o Pompholyx -vesiculobullous eruption on palms and soles
o Varicose - associated with marked varicose veins
o Nummular - coin shaped, on legs and trunk
o Asteatotic - dry, crazy paring pattern
Investigations for eczema
• Contact Eczema
o Skin patch testing - a disc containing allergens is diluted and applied on the skin
for 48 hrs. It is positive if it causes a red raised lesion
• Atopic Eczema
o Lab testing e.g. IgE levels
Define Erythema Multiforme
An acute hypersensitivity reaction of the skin and mucous membranes. Stevens-Johnson syndrome is a severe form with bullies lesions and necrotic ulcers
Aetiology/ Risk factors of erythema multiforme
• Degeneration of basal epidermal cells
• Development of vesicles between cells in the basement membrane
• Lymphocytic infiltrate around the blood vessels and at the dermo-epidermal junction
• A precipitating factor is only identified 50% of the time
• Precipitating Factors:
o Drugs - e.g. sulphonamides, penicillin, phenytoin
o Infection - e.g. HSV, EBV, adenovirus, chlamydia, histoplasmosis
o Inflammatory - e.g. rheumatoid arthritis, SLE, sarcoidosis, ulcerative colitis o Malignancy - e.g. lymphomas, leukaemia, myeloma
o Radiotherapy
Summarise the epidemiology of erythema multiforme
- Any age group
- Mainly in CHILDREN and YOUNG ADULTS
- TWICE as common in MALES
Presenting symptoms of erythema multiforme
- Non-specific prodromal symptoms of upper respiratory tract infection
- Sudden appearance of itching/burning/painful skin lesions
- Skin lesions may fade leaving pigmentation
Recognise the signs of erythema multiforme
• Classic target (bull’s eye) lesions with a rim of erythema surrounding a paler area
• Vesicles/bullae
• Urticarial plaques
• Lesions are often symmetrical and distributed
over the arms and legs including the palms, soles
and extensor surfaces
• Stevens-Johnson syndrome is characterised by:
o Affecting > 2 mucous membranes (e.g. conjunctiva, cornea, lips, mouth, genitalia)
o Systemic symptoms (e.g. sore throat, cough, fever, headache, myalgia, arthralgia, diarrhoea/vomiting)
o Shock (hypotension and tachycardia)
Investigations for erythema multiforme
• Usually unnecessary - erythema multiforme is very much a clinical diagnosis
• Bloods
o High WC, eosinophils, ESR/CRP
• Imaging - exclude sarcoidosis and atypical pneumonia
• Skin biopsy - histology and direct immunofluorescence if in doubt about diagnosis
Define Erythema Nodosum
Panniculitis (inflammation of subcutaneous fat tissue) presenting as red or violet subcutaneous nodules
Aetiology/ Risk factors of erythema nodosum
• Delayed hypersensitivity reaction to antigens associated with various infectious agents, drugs and diseases • Infection o Bacterial - e.g. streptococcus o Viral - e.g. EBV o Fungal - e.g. histoplasmosis • Systemic Disease o Sarcoidosis o IBD o Behcet's disease • Malignancy o Leukaemia o Hodgkin's disease • Drugs o Sulphonamides o Penicillin o Oral contraceptive pills • Pregnancy • 25% of cases have no identifiable cause
epidemiology of erythema nodosum
- Usually affects YOUNG ADULTS
* THREE times more common in FEMALES
Presenting symptoms of erythema nodosum
• Tender red or violet nodules bilaterally on both shins • Occasionally on thighs or forearms • Fatigue • Fever • Anorexia • Weight loss • Arthralgia • Symptoms of underlying CAUSE
Signs of erythema nodosum on clinical examination
- Crops of red or violet dome-shaped nodules usually present on both shins
- Occasionally appear on the thighs and forearms
- Nodules are tender to palpation
- Low-grade pyrexia
- Joints may be tender and painful on movement
- Signs of underlying CAUSE
Investigations for erythema nodosum
• Determine underlying CAUSE
• Bloods
o Anti-streptolysin-O titres (check for streptococcal infection)
o FBC/CRP/ESR - check for signs of infection/inflammation
o U&Es
o Serum ACE (raised in sarcoidosis)
• Throat swab and cultures
• Mantoux/Head skin testing - for TB
• CXR - check for bilateral hilar lymphadenopathy or other evidence of TB, sarcoidosis or fungal infections
Define Lipoma
Slow-growing, benign adipose tumours that are most often found in the subcutaneous tissues
