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
Aetiology/ Risk Factors of lipoma
• Benign tumours of adipocytes • Conditions associated with lipomas o Familial multiple lipomatosis: o Gardner's syndrome o Dercum's disease o Madelung's disease • Liposarcoma - rare malignant tumour of adipose tissue
Epidemiology of lipomas
- Seen at any age but more common between 40-60yrs
- relatively common
Presenting symptoms/ signs of Lipoma
- Most are ASYMPTOMATIC
- Compression of nerves can cause pain
- Soft or firm nodule
- Smooth normal surface
- Skin coloured
- Most are < 5 cm in diameter • Mobile
- Soft/doughy feel
Investigations for lipoma
- usually CLINICAL diagnosis
- US/MRI/CT used if there is doubt about the diagnosis
Define Melanoma
Malignancy arising from neoplastic transformation of melanocytes, the pigment-forming skin cells. The leading cause of death from skin disease
Aetiology/ Risk factors of melanoma
• DNA damage caused by ultraviolet radiation leads to neoplastic transformation
• 50% arise in existing naevi
• 50% arise in previously normal skin
• FOUR histopathological types:
o Superficial Spreading (70%)
• Arises in a pre-existing naevus, expands in a radial fashion before a vertical
growth phase
o Nodular (15%)
• Arises de novo
• AGGRESSIVE
• NO radial growth phase
o Lentigo Maligna (10%)
• More common in ELDERLY with sun damage
• Large flat lesions
• Progresses slowly
• Usually on the face
o Acral Lentiginous (5%)
• Arise on palms, soles and subungual areas
• Most common type in NON-WHITE populations
Epidemiology of melanoma
- Steadily increasing in incidence
- White races have 20x increased risk compared to non-whites
Presenting symptoms of melanoma
- Change in size, shape or colour of a pigmented skin lesion
- Redness
- Bleeding
- Crusting
- Ulceration
Signs of melanoma on physical examination
ABCDE criteria for examining moles A- asymmetry B- border irregularity C- colour variation D- diameter >6mm E- elevation/ evolution
Identify investigations for melanoma
• Excisional Biopsy - histological diagnosis and determination of Clark’s Levels and
Breslow Thickness (two methods of determining the depth of penetration of a melanoma)
• Lymphoscintigraphy - a radioactive compound is injected into the lesion and images are taken over 30 mins to trace the lymph drainage and identify the sentinel nodes
• Sentinel Lymph Node Biopsy - check for metastatic involvement
• Staging - using ultrasound, CT or MRI, CXR
• Bloods - LFTs (because the liver is a common site of metastasis)
Define Molluscum Contagiosum
A common skin infection caused by a pox virus that affects children and adults. Transmission is usually by direct skin contact
Aetiology/ Risk Factors of Molluscum Contagiosum
• Viral skin infection caused by molluscum contagiosum virus (MCV) • It is a type of pox virus • Risk Factors o Mainly in CHILDREN o Immunocompromised o Atopic eczema
Epidemiology of molluscum contagiosum
- COMMON
- 90% of patients are < 15 yrs
- A lot of people will not seek medical attention for it
Presenting symptoms of molluscum contagiosum
- Incubation period: 2-8 weeks
- Usually ASYMPTOMATIC
- There may be tenderness, pruritus and eczema around the lesion
- Lesions last for around 8 months
Signs of molluscum contagiosum on physical examination
• Firm, smooth, umbilicated papules
• Usually 2-5 mm in diameter
• In children - tends to occur on the trunk
and the extremities
• In adults - tends to occur on the lower
abdomen, genital area and inner thighs
(suggesting sexual contact)
Investigations for molluscum contagiosum
- Usually a CLINICAL diagnosis
* Dermatoscopy may be useful if there is doubt
Define Pressure Sores
Damage to the skin, usually over a bony prominence, as a result of pressure
Aetiology/ Risk Factors of pressure sores
• Constant pressure limits blood flow to the skin leading to tissue damage
• They occur as a result of pressure, friction and shear
• Risk Factors:
o IMMOBILITY
o Alzheimer’s disease
o Diabetes
Epidemiology of pressure sores
- Very COMMON in hospitals
* Most commonly occurs in the ELDERLY
Presenting symptoms and signs of pressure sores
• Occurs over bony prominences - most commonly the
SACRUM and HEEL
• Pressure scores can be staged from Stage 1-4
• They are very TENDER
• They may become infected leading to fevers, erythema and foul smell
Investigations for pressure sores
- NO investigations necessary
- Clinical diagnosis
- Waterlow Score is used to predict risk of pressure sores in patients
Define Psoriasis
A chronic inflammatory skin disease, which has characteristic lesions and may be complicated by arthritis
Aetiology/ Risk Factors of Psoriasis
• UNKNOWN
• Genetic, environmental factors and drugs are implicated
• Risk Factors
o Guttate psoriasis - streptococcal sore throat
o Palmoplantar psoriasis - smoking, middle-aged women, autoimmune thyroid
disease
o Generalised pustular psoriasis - hypoparathyroidism
Epidemiology of Psoriasis
• Affects 1-2% of population • Peak age of onset: 20 yrs
Presenting symptoms of Psoriasis
- Itching and occasionally tender skin
- Pinpoint bleeding with removing scales (Auspitz phenomenon)
- Skin lesions may develop at sites of trauma/scars (Koebner phenomenon)
Signs of Psoriasis on physical examination
• Discoid/Nummular psoriasis - symmetrical, well-demarcated erythematous plaques with silvery scales over extensor surfaces (knee, elbows, scalp, sacrum)
• Flexural psoriasis - less scaly plaques in axilla, groins, perianal and genital skin
• Guttate psoriasis - small drop-like lesions over trunk and limbs
• Palmoplantar psoriasis - erythematous plaques with pustules on palms and soles
• Generalised pustular psoriasis - pustules distributed over limbs and torso
• Nail Signs
o Pitting
o Onycholysis
o Subungual hyperkeratosis
• Joint Signs - FIVE presentations of psoriatic arthritis:
o Asymmetrical oligoarthritis
o Symmetrical polyarthritis
o Distal interphalangeal joint predominance
o Arthritis mutilans
o Psoriatic spondylitis
Investigations for Psoriasis
- Most patients DO NOT need investigations
- Guttate psoriasis -anti-streptolysin-O titre, throat swab
- Flexural psoriasis - skin swabs to exclude candidiasis
- Nail clipping analysis for onychomycosis (fungal infection)
- Joint involvement analysed by checking for rheumatoid factor and radiographs
Define Sebaceous Cysts
Eptihelium-lined, keratinous, debris-filled cyst arising from a blocked hair follicle. Also known as an epidermal cyst
Aetiology/ Risk Factors of sebaceous cycts
• Occlusion of the pilosebaceous gland
• Can be caused by traumatic insertion of epidermal elements into the dermis
• Embryonic remnants
• Risk Factors
o Gardner’s Syndrome = autosomal dominant condition characterised by the presence of multiple polyps in the colon and in extra-colonic sites (e.g. sebaceous cyst, thyroid cancer, fibroma)
Epidemiology of sebaceous cysts
• VERY COMMON at any age
Presenting symptoms of sebaceous cysts
- Non-tender slow-growing skin swelling
- There are often multiple
- Common on hair-bearing regions of the body (e.g. face, scalp, trunk or scrotum)
- May become red, hot and tender if there is superimposed infection or inflammation
Signs of sebaceous cysts on physical examination
- Smooth tethered lump
- Overlying skin punctum
- May discharge granular creamy material that smells bad
Investigations for sebaceous cysts on physical examination
- NONE needed
* Skin biopsy or FNA may be used to rule out other differentials
Management plan for sebaceous cysts
• Conservative
o May be left alone if its not causing the patient any distress
• Surgical
o Excision of the cyst under local anaesthesia
• Medical
o Antibiotics if there is an infection
Possible complications of sebaceous cysts
- Infection
- Abscess formation
- Recurrence (if incomplete excision)
- May ulcerate
Prognosis for patients with sebaceous cysts
- EXCELLENT
* Most do NOT require treatment
Define Squamous Cell Carcinoma
Malignancy of epidermal keratinocytes of the skin
o Marjolin’s ulcer is a squamous cell carcinoma that arises in an area of chronically inflamed skin
Aetiology/ Risk Factors of squamous cell carcinoma
• Main risk factor = UV RADIATION
• Sun exposure can lead to actinic keratosis (sun-induced precancerous lesion)
• Other risk factors:
o Radiation
o Carcinogens (e.g. tar derivatives, cigarette smoke) o Chronic skin disease (e.g. lupus)
o HPV
o Long-term immunosuppression
o Defects in DNA repair (xeroderma pigmentosum)
Epidemiology of squamous cell carcinoma
- SECOND most common cutaneous malignancy (20% of all skin cancers)
- Occurs mainly in MIDDLEMAGED and ELDERLY people
- LIGHT-SKINNED individuals are at higher risk
- 2-3 x more common in MALES
Presenting symptoms of squamous cell carcinoma
- Skin lesion
- Ulcerated
- Recurrent bleeding
- Non-healing
Signs of squamous cell carcinoma on physical examination
- Variable appearance - may be ulcerated, hyperkeratotic, crusted or scaly, non-healing • Often on sun-exposed areas
- Palpate for local lymphadenopathy
Investigations for squamous cell carcinoma
- Skin Biopsy - confirm malignancy and specific type
- Fine-needle aspiration or lymph node biopsy - if metastasis is suspected
- Staging - using CT, MRI or PET
Define Urticaria
Itchy, red, blotchy rash resulting from swelling of the superficial part of the skin. Angioedema occurs when the deep tissues, the lower dermis and subcutaneous tissues are involved and become swollen.
- AKA hives
Aetiology / Risk Factors of Urticaria
• Caused by activation of mast cells in the skin, resulting in the release of histamines
• The cytokine release leads to capillary leakage, which causes swelling of the skin and
vasodilation –> erythematous appearance
• Possible Triggers:
o ACUTE urticaria
• Allergies (foods, bites, stings)
• Viral infections
• Skin contact with chemicals
• Physical stimuli
o CHRONIC urticaria
• Autoimmune
• Chronic spontaneous urticaria- medication, stress, infections
Epidemiology of Urticaria
- 15% of general population experience urticaria at some point in life
- Acute is much more common than chronic urticaria
Recognise presenting symptoms and signs of urticaria
• Central itchy white papule or plaque surrounded by
erythematous flare
• Lesions vary in size and shape
• May be associated with swelling of the soft-tissues of
the eyelids, lips and tongue (angiooedema)
• Individual lesions are usually transient
• Timescales:
o Acute - symptoms develop quickly but normally resolve within 48 hrs
o Chronic - rash persists for > 6 weeks
Investigations for urticaria
- Usually clinical
- Tests may be required for chronic urticaria (e.g. FBC, ESR/CRP, patch testing, IgE tests
