Dermatology Flashcards
Define basal cell carcinoma
• COMMONEST form of skin malignancy, also known as a rodent ulcer
Explain the 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
Summarise the 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
Recognise the 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
Nodulo-ulcerative (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 ill-defined 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
Identify appropriate investigations for basal cell carcinoma and interpret the results
- Biopsy is RARELY necessary
* Diagnosis is mainly on clinical suspicion
Define burns injury
When tissue damage occurs by thermal, electrical or chemical injury
Explain the aetiology / risk factors of burns injury
• Contact with hot objects (lol) • Electricity • UV light • Irradiation • Chemicals High Risk Patients o Young children o Elderly
Summarise the epidemiology of burns injury
UK has > 12,000 admission per year
Recognise the presenting symptoms of burns injury
Note the circumstances of the burn
Important to find out the time, temperature and length of contact with the agent
Consider risk of smoke inhalation and carbon monoxide poisoning
Recognise the signs of burns injury on physical examination
Check for inhalational injury or airway compromise:
o Stridor
o Dyspnoea
o Hoarse voice
o Soot in nose
o Singed nose hairs
o Carbonaceous sputum
Check site, depth and distribution of burn
Partial Thickness Burn
o Subdivided into:
Superficial: red and oedematous skin + PAINFUL
Heals within around 7 days with peeling of dead skin
Deep: blistering and mottling + PAINFUL
Heals over 3 weeks, usually without scarring
Full Thickness Burn
o Destruction of the epidermis and dermis
o Charred leathery eschars
o Firm and PAINLESS with loss of sensation
o Healing will occur by scarring or contractures and requires skin grafting
• Size of Burn
o Described as a percentage of body surface area
Identify appropriate investigations for burns injury and interpret the results
Bloods o Oxygen saturation, ABG and carboxyhaemoglobin (if inhalational injury) o FBC o U&Es o Group and Save Investigations for electrical burns o Serum CK o Urine myoglobin (check for muscle damage) o ECG
Define candidiasis
• Infection caused by Candida.
Explain the aetiology/risk factors of candidiasis
- Caused by 15 different Candida species
- Candida albicans is the MOST COMMON cause of candidiasis in humans
Main types of candidiasis: o Oral candidiasis o Oesophageal candidiasis o Candidal vulvovaginitis o Candidal skin infections o Invasive candidal infections
Risk Factors o Broad-spectrum antibiotics o Immunocompromise (e.g. HIV, corticosteroids) o Central venous lines o Cushing's disease o Diabetes mellitus o GI tract surgery
Summarise the epidemiology of candidiasis
- 60% of the healthy adult population are carriers
- Candidiasis occurs in over 80% of people with HIV
- Candida is one of the most common causes of invasive fungal infections in the Western world
Recognise the presenting symptoms and signs of candidiasis
• Oral Candidiasis
o Oral Thrush (pseudomembranous oral candidiasis) - curd-like white patches in the mouth, which can be removed easily revealing an underlying red base. Most common in neonates
o There are lots of subtypes of oral candidiasis with slightly different features but the main features are: redness of the tongue and mouth, white plaques
• Oesophageal Candidiasis
o Dysphagia
o Pain on swallowing food or fluids
o It is an AIDS-defining illness
• Candidal Skin Infections
o Soreness and itching
o Skin appearance can be variable
o Red, moist skin area with ragged, peeling edge and possibly papules and pustules
Identify appropriate investigations for candidiasis
- Oral Candidiasis - swabs and cultures are not particularly useful because a lot of normal people have candida in their mouth
- Swabs may be relevant to check for drug-resistance
- Therapeutic trials of antifungal (e.g. fluconazole) can help with diagnosis
- Oesophageal Candidiasis: definitive diagnosis is by endoscopy
- Invasive Candidiasis: blood cultures required if candidaemia is possible
Define cellulitis
• Acute non-purulent spreading infection of the subcutaneous tissue, causing overlying skin inflammation
Explain the aetiology/risk factors of cellulitis
• Often results from: o Penetrating injury o Local lesions (e.g. insect bits) o Fissuring (e.g. anal fissures) • These allow pathogenic bacteria to enter the skin • Most common organisms o Streptococcus pyogenes o Staphylococcus aureus o NOTE: beware of MRSA • Cellulitis of the orbit (orbital cellulitis) is usually caused by Haemophilus influenzae • Risk Factors o Skin break o Poor hygiene o Poor vascularisation of tissue (e.g. due to diabetes mellitus)
Summarise the epidemiology of cellulitis
• VERY COMMON
Recognise the presenting symptoms of cellulitis
- History of cut, scratch or injury
- Periorbital Cellulitis - painful swollen red skin around the eye
• Orbital Cellulitis - painful or limited eye movements, visual impairment
Recognise the signs of cellulitis on physical examination
• Lesion o Erythema o Oedema o Warm tender indistinct margins o Pyrexia - may suggest systemic spread • NOTE: exclude the presence of an abscess (aspirate if pus suspected) • Periorbital o Swollen eye lids o Conjunctival infection • Orbital Cellulitis o Proptosis o Impaired visual acuity and eye movements o Test for RAPD , visual acuity and colour vision
Identify appropriate investigations for cellulitis
- Bloods - WCC, blood culture
- Discharge - sample and send for MC&S
- Aspiration (if pus is suspected)
- CT/MRI - if orbital cellulitis is suspected (helps assess posterior spread of infection)
Generate a management plan for cellulitis
• Medical
o Oral penicillins (e.g. flucloxacillin) or tetracyclines are effective
o If hospital-acquired - treat empirically based on local guidelines and change depending on the sensitivity of cultured organisms
• Surgical
o Orbital decompression may be needed in orbital cellulitis (EMERGENCY)
• Abscess
o Aspirate
o Incision and drainage
o Excised completely
Identify possible complications of cellulitis
- Sloughing of overlying skin
- Orbital cellulitis - may cause permanent loss of vision, spread to the brain, abscess formation, meningitis, cavernous sinus thrombosis
Summarise the prognosis for patients with cellulitis
• Good prognosis
Define eczema
• A pruritic papulovesicular skin reaction to endogenous and exogenous agents
Explain the 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
Summarise the 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 9eg.. Bleach)
- Ask about personal/family history of atopy (e.g. asthma, hay fever)
Recognise the 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
Identify appropriate 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 sebaceous cyst
• Epithelium-lined, keratinous, debris-filled cyst arising from a blocked hair follicle. Also known as an epidermal cyst.
Explain the aetiology/risk factors of sebaceous cysts
• 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)
Summarise the epidemiology of sebaceous cysts
• VERY COMMON at any age
Recognise the 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
Recognise the signs of sebaceous cysts on physical examination
- Smooth tethered lump
- Overlying skin punctum
- May discharge granular creamy material that smells bad
Identify appropriate investigations for sebaceous cysts
- NONE needed
* Skin biopsy or FNA may be used to rule out other differentials
Generate a 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
Identify possible complications of sebaceous cysts
- Infection
- Abscess formation
- Recurrence (if incomplete excision)
- May ulcerate
Summarise the prognosis for patients with sebaceous cysts
- EXCELLENT
* Most do NOT require treatment
Define erythema multiforme
• An acute hypersensitivity reaction of the skin and mucous membranes. Stevens-Johnson syndrome is a severe form with bullous lesions and necrotic ulcers