Derm Flashcards
What is erythema multiforme
Features
Erythema multiforme is a hypersensitivity reaction which is most commonly triggered by infections. It may be divided into minor and major forms.
Previously it was thought that Stevens-Johnson syndrome (SJS) was a severe form of erythema multiforme. They are now however considered as separate entities.
Features
TARGET LESIONS
Initially seen on the back of the hands / feet before spreading to the torso
Upper limbs are more commonly affected than the lower limbs
Pruritus is occasionally seen and is usually mild
Causes viruses: HSV (the most common cause), Orf* idiopathic bacteria: Mycoplasma, Streptococcus drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine connective tissue disease e.g. SLE SARCOIDOSIS malignancy
What is erythema nodosum
Features
Causes
Inflammation of subcutaneous fat
Typically causes tender, erythematous, nodular lesions
usually occurs over shins, may also occur elsewhere (e.g. forearms, thighs)
Usually resolves within 6 weeks
Lesions heal without scarring
Causes
NO – idiopathic
D – drugs (penicillin sulphonamides)
O – oral contraceptive/pregnancy
S – sarcoidosis/TB
U – ulcerative colitis/Crohn’s disease/Behçet’s disease
M – microbiology (streptococcus, mycoplasma, EBV and more)
Tests
Useful tests include chest X-ray, complete blood count, urinalysis, throat culture, antistreptolysin-O titre, tuberculin skin test.
What is lichen planus
Features
Causes
management
Lichen planus is a skin disorder of unknown aetiology, most probably being immune-mediated.
Features
Itchy, papular purple rash most common on the palms, soles, genitalia and flexor surfaces of arms
rash often polygonal in shape, with a ‘white-lines’ pattern on the surface (Wickham’s striae)
Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
nails: thinning of nail plate, longitudinal ridging
planus: purple, pruritic, papular, polygonal rash on flexor surfaces. Wickham’s striae over surface. Oral involvement common
Lichenoid drug eruptions - causes:
gold
quinine
thiazides
Management
topical steroids are the mainstay of treatment
benzydamine mouthwash or spray is recommended for oral lichen planus
extensive lichen planus may require oral steroids or immunosuppression
Acne vulgaris treatment
A simple step-up management scheme often used in the treatment of acne is as follows:
1) single topical therapy (topical retinoids, benzoyl peroxide)
2) Topical combination therapy (topical antibiotic, benzoyl peroxide, topical retinoid)
3) Oral antibiotics:
- tetracyclines: lymecycline, oxytetracycline, doxycycline
(tetracyclines should be avoided in pregnant or breastfeeding women and in children younger than 12 years of age - erythromycin may be used in pregnancy
minocycline is now considered less appropriate due to the possibility of irreversible pigmentation
- a single oral antibiotic for acne vulgaris should be used for a maximum of three months
- a topical retinoid (if not contraindicated) or benzoyl peroxide should ALWAYS be co-prescribed with oral antibiotics to reduce the risk of antibiotic resistance developing. Topical and oral antibiotics should not be used in combination
Gram-negative folliculitis may occur as a complication of long-term antibiotic use - high-dose oral trimethoprim is effective if this occurs
4) combined oral contraceptives (COCP) are an alternative to oral antibiotics in women
- as with antibiotics, they should be used in combination with topical agents
- Dianette (co-cyrindiol) is sometimes used as it has anti-androgen properties. However, it has an increased risk of venous thromboembolism compared to other COCPs, therefore it should generally be used second-line, only be given for 3 months and women should be appropriately counselled about the risks
Oral isotretinoin: only under specialist supervision
pregnancy is a contraindication to topical and oral retinoid treatment
What is acne vulgariss
Treatment
Acne vulgaris is a common skin disorder which usually occurs in adolescence. It typically affects the face, neck and upper trunk and is characterised by the obstruction of the pilosebaceous follicles with keratin plugs which results in comedones, inflammation and pustules.
Acne may be classified into mild, moderate or severe:
Mild = open and closed comedones with or without sparse inflammatory lesions
Moderate acne: widespread non-inflammatory lesions and numerous papules and pustules
Severe acne: extensive inflammatory lesions, which may include nodules, pitting, and scarring
What is pityriasis rosacea
Features
Pityriasis rosea describes an acute, self-limiting rash which tends to affect young adults. The aetiology is not fully understood but is thought that herpes hominis virus 7 (HHV-7) may play a role.
Features
in the majority of patients there is no prodrome, but a minority may give a history of a recent viral infection
herald patch (usually on trunk)
followed by erythematous, oval, scaly patches which follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a ‘fir-tree’ appearance
Management
self-limitingm - usually disappears after 6-12 weeks
Management of fungal nail infections
Management
DON’T TREAT IF asymptomatic and the patient is not bothered by the appearance
Diagnosis should be confirmed by microbiology before starting treatment
Dermatophyte infection:
Oral terbinafine is currently recommended first-line with oral itraconazole as an alternative
- 6 weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months
Treatment is successful in around 50-80% of people
Candida infection:
Mild disease should be treated with topical antifungals (e.g. Amorolfine) whilst more severe infections should be treated with oral itraconazole for a period of 12 weeks
if topical topical treatment is given treatment should be continued for 6 months for fingernails and 9-12 months for toenails
What is bullious pemphigoid
Features
Investigation
Management
Bullous pemphigoid is an autoimmune condition causing sub-epidermal blistering of the skin. This is secondary to the development of antibodies against hemidesmosomal proteins BP180 and BP230
Bullous pemphigoid is more common in ELDERLY patients. Features include
Itchy, tense blisters typically around FLEXURES
the blisters usually heal without scarring
Mouth is usually spared*
Skin biopsy
immunofluorescence shows IgG and C3 at the dermoepidermal junction
Management
Referral to dermatologist for biopsy and confirmation of diagnosis
Oral corticosteroids are the mainstay of treatment
topical corticosteroids, immunosuppressants and antibiotics are also used
What exacerbates psoriasis
Trauma
Alcohol
drugs: beta blockers, LITHIUM, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids
Streptococcal infection may trigger guttate psoriasis.
What is pyogenic granuloma
Cause
Features
Management
Pyogenic granuloma is a relatively common benign skin lesion. The name is confusing as they are neither true granulomas nor pyogenic in nature. There are multiple alternative names but perhaps ‘eruptive haemangioma’ is the most useful.
= Overgrowth of blood vessels
The cause of pyogenic granuloma is not known but a number of factors are linked:
TRAUMA
pregnancy
more common in women and young adults
Features
most common sites are head/neck, upper trunk and hands. Lesions in the oral mucosa are common in pregnancy
initially small red/brown spot
rapidly progress within days to weeks forming raised, red/brown lesions which are often spherical in shape
the lesions may bleed profusely or ulcerate
Management
lesions associated with pregnancy often resolve spontaneously post-partum
other lesions usually persist. Removal methods include curettage and cauterisation, cryotherapy, excision
Acne rosacea features
Features Typically affects nose, cheeks and forehead Flushing is often first symptom Telangiectasia are common Later develops into persistent erythema with papules and pustules Rhinophyma Ocular involvement: blepharitis Sunlight may exacerbate symptoms/
Acne rosacea management
Topical metronidazole may be used for mild symptoms (i.e. Limited number of papules and pustules, no plaques)
Topical brimonidine gel may be considered for patients with predominant flushing but limited telangiectasia
More severe disease is treated with systemic antibiotics e.g. Oxytetracycline
Recommend daily application of a high-factor sunscreen
camouflage creams may help conceal redness
Laser therapy may be appropriate for patients with prominent telangiectasia
Patients with a rhinophyma should be referred to dermatology
Pemphigus vulgaris what is it
Features
Management
emphigus vulgaris is an autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule. It is more common in the Ashkenazi Jewish population.
Antibodies target the desmosomes that connect the cells
Features
- Mucosal ulceration is common and often the presenting symptom. Oral involvement is seen in 50-70% of patients
-Skin blistering - flaccid, easily ruptured vesicles and bullae. - Lesions are typically painful but not itchy. These may develop months after the initial mucosal symptoms.
- Nikolsky’s describes the spread of bullae following application of horizontal, tangential pressure to the skin
acantholysis on biopsy
Management
steroids are first-line
immunosuppressants
Pyoderma gangrenosum
Causes
Management
Features
Initially small red papule
–> later deep, red, necrotic ulcers with a violaceous border
Causes
Idiopathic in 50%, may also be seen in IBD, connective tissue disorders and myeloproliferative disorders
Management
the potential for rapid progression is high in most patients and most doctors advocate oral steroids as first-line treatment
other immunosuppressive therapy, for example ciclosporin and infliximab, have a role in difficult cases
Guttate psoriasis
Epidemiology
Features
Management
Guttate psoriasis is more common in children and adolescents. It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing.
Features
tear drop papules on the trunk and limbs
Management
- Most cases resolve spontaneously within 2-3 months
there is no firm evidence to support the use of antibiotics to eradicate streptococcal infection
- Topical agents as per psoriasis
- UVB phototherapy
- Tonsillectomy may be necessary with recurrent episodes
What is a dermatitis herpetiformis
Features
Diagnosis
Management
Dermatitis herpetiformis is an autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
Features
Itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks)
Diagnosis
skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis
Management
gluten-free diet
dapsone
Isotretinoin
Use
Adverse effects
Isotretinoin is an oral retinoid used in the treatment of severe acne. Two-thirds of patients have a long-term remission or cure following a course of oral isotretinoin.
Adverse effects
Teratogenicity: females should ideally be using two forms of contraception (e.g. Combined oral contraceptive pill and condoms)
Dry skin, eyes and lips/mouth: the most common side-effect of isotretinoin
Low mood*
Raised triglycerides
Hair thinning
Nose bleeds (caused by dryness of the nasal mucosa)
Intracranial hypertension: isotretinoin treatment should not be combined with tetracyclines for this reason
photosensitivity
Actinic keratosis
Definition
Cause
Features
Management
Actinic, or solar, keratoses (AK) is a common premalignant skin lesion that develops as a consequence of chronic sun exposure
Features
small, crusty or scaly, lesions
may be pink, red, brown or the same colour as the skin
typically on sun-exposed areas e.g. temples of head
multiple lesions may be present
Management options include
Prevention of further risk: e.g. sun avoidance, sun cream
Fluorouracil cream: typically a 2 to 3 week course. The skin will become red and inflamed - sometimes topical hydrocortisone is given following fluorouracil to help settle the inflammation
Topical diclofenac: may be used for mild AKs. Moderate efficacy but much fewer side-effects
Topical imiquimod: trials have shown good efficacy
Cryotherapy
Curettage and cautery
Hyperhidrosis
Management
Hyperhidrosis describes the excessive production of sweat.
Management options include
Topical aluminium chloride preparations are first-line. Main side effect is skin irritation
Iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis
Botulinum toxin: currently licensed for axillary symptoms
Surgery: e.g. Endoscopic transthoracic sympathectomy.
Patients should be made aware of the risk of compensatory sweating
Erythema ab igne
Cause
Features
Consequence
Erythema ab igne is a skin disorder caused by over exposure to infrared radiation.
Characteristic features include reticulated, erythematous patches with hyperpigmentation and telangiectasia. A typical history would be an elderly women who always sits next to an open fire.
If the cause is not treated then patients may go on to develop squamous cell skin cancer.
Keratoacanthoma definition
Features
Management
Keratoacanthoma is a benign epithelial tumour. They are more common with advancing age and rare in young people.
Features - said to look like a volcano or crater
initially a smooth dome-shaped papule
rapidly grows to become a crater centrally-filled with keratin
Spontaneous regression of keratoacanthoma within 3 months is common, often resulting in a scar. Such lesions should however be urgently excised as it is difficult clinically to exclude squamous cell carcinoma. Removal also may prevent scarring.
Squamous cell cancer risk factors
Management
Squamous cell carcinoma is a common variant of skin cancer. Metastases are rare but may occur in 2-5% of patients.
Risk factors include:
Excessive exposure to sunlight / psoralen UVA therapy
Actinic keratoses and Bowen’s disease
immunosuppression e.g. following renal transplant, HIV
smoking
long-standing leg ulcers (Marjolin’s ulcer)
genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism
Management
Surgical excision with 4mm margins if lesion <20mm in diameter.
If tumour >20mm then margins should be 6mm.
Mohs micrographic surgery may be used in high-risk patients and in cosmetically important sites.
Athlete’s foot
AKA
Cause
Features
Management
Athlete’s foot
Athlete’s foot is also known as tinea pedis. It is usually caused by fungi in the genus Trichophyton.
Features
typically scaling, flaking, and itching between the toes
Clinical knowledge summaries recommend a topical imidazole (e.g. miconazole), undecenoate, or terbinafine first-line
Lipoma definition
Epidemiology
Features
Management
A lipoma is a common, benign tumour of adipocytes.
Pathophysiology
they are generally found in subcutaneous tissues
rarely, they may also occur in deeper adipose tissues
malignant transformation to liposarcoma is very rare
Epidemiology
lipomas are common, with an annual incidence of around 1 in 1,000
most commonly seen in middle-aged adults
Features lump characteristics: smooth mobile painless
The diagnosis is usually clinical based on the typical examination findings.
Management
may be observed
if diagnosis uncertain, or compressing on surrounding structures then may be removed
Liposarcoma
Features suggestive of sarcomatous change --US tp rule out Size >5cm Increasing size Pain Deep anatomical location
Hereditary haemorrhagic telangiectasia
AKA
Also known as Osler-Weber-Rendu syndrome, hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant condition characterised by (as the name suggests) multiple telangiectasia over the skin and mucous membranes. Twenty percent of cases occur spontaneously without prior family history.
There are 4 main diagnostic criteria. If the patient has 2 then they are said to have a possible diagnosis of HHT. If they meet 3 or more of the criteria they are said to have a definite diagnosis of HHT:
1) EPISTAXIS : spontaneous, recurrent nosebleeds
2) TELANGECTASIAs: multiple at characteristic sites (lips, oral cavity, fingers, nose)
3) Visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
4) FH: a first-degree relative with HHT
Seborrhoeic keratoses
Define
Features
Management
Seborrhoeic keratoses are benign epidermal skin lesions seen in older people.
Features
large variation in colour from flesh to light-brown to black
have a ‘stuck-on’ appearance, warty appearance
keratotic plugs may be seen on the surface
Management
reassurance about the benign nature of the lesion is an option
options for removal include curettage, cryosurgery and shave biopsy
Scabies
Cause
Features
Management
Scabies
Scabies is caused by the mite Sarcoptes scabiei and is spread by prolonged skin contact. It typically affects children and young adults.
The scabies mite burrows into the skin, laying its eggs in the stratum corneum. The intense pruritus associated with scabies is due to a delayed-type IV hypersensitivity reaction to mites/eggs which occurs about 30 days after the initial infection.
Features
widespread pruritus
linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
in infants, the face and scalp may also be affected
secondary features are seen due to scratching: excoriation, infection
Management
permethrin 5% is first-line
malathion 0.5% is second-line
give appropriate guidance on use (see below)
pruritus persists for up to 4-6 weeks post eradication
Patient guidance on treatment (from Clinical Knowledge Summaries)
avoid close physical contact with others until treatment is complete
all household and close physical contacts should be treated at the same time, even if asymptomatic
launder, iron or tumble dry clothing, bedding, towels, etc., on the first day of treatment to kill off mites.
The BNF advises to apply the insecticide to all areas, including the face and scalp, contrary to the manufacturer’s recommendation. Patients should be given the following instructions:
apply the insecticide cream or liquid to cool, dry skin
pay close attention to areas between fingers and toes, under nails, armpit area, creases of the skin such as at the wrist and elbow
allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
reapply if insecticide is removed during the treatment period, e.g. If wash hands, change nappy, etc
repeat treatment 7 days later
Burns extent calculation
Wallace’s Rule of Nines: head + neck = 9%, each arm = 9%, each anterior part of leg = 9%, each posterior part of leg = 9%, anterior chest = 9%, posterior chest = 9%, anterior abdomen = 9%, posterior abdomen = 9%
Lund and Browder chart: the most accurate method
the palmar surface is roughly equivalent to 1% of total body surface area (TBSA). Not accurate for burns > 15% TBSA
burns that need referral to secondary care
All deep dermal and full-thickness burns.
Superficial dermal burns of more than 3% TBSA in adults, or more than 2% TBSA in children
Superficial dermal burns involving the face, hands, feet, perineum, genitalia, or any flexure, or circumferential burns of the limbs, torso, or neck
Any inhalation injury
Any electrical or chemical burn injury
Suspicion of non-accidental injury
Management of more severe burns
The initial aim is to stop the burning process and resuscitate the patient. Intravenous fluids will be required for children with burns greater than 10% of total body surface area. Adults with burns greater than 15% of total body surface area will also require IV fluids.
The fluids are calculated using the Parkland formula which is; volume of fluid
= total body surface area of the burn % x weight (Kg) x4.
Half of the fluid is administered in the first 8 hours.
A urinary catheter should be inserted.
Analgesia should be given.
Complex burns, burns involving the hand perineum and face and burns >10% in adults and >5% in children should be transferred to a burns unit.
Circumferential burns affecting a limb or severe torso burns impeding respiration may require escharotomy to divide the burnt tissue.
Conservative management is appropriate for superficial burns and mixed superficial burns that will heal in 2 weeks. More complex burns may require excision and skin grafting. Excision and primary closure is not generally practised as there is a high risk of infection.
There is no evidence to support the use of anti microbial prophylaxis or topical antibiotics in burn patients.
Escharotomies
Indicated in circumferential full thickness burns to the torso or limbs.
Careful division of the encasing band of burn tissue will potentially improve ventilation (if the burn involves the torso), or relieve compartment syndrome and oedema (where a limb is involved)
What is TEN
Features
Drugs known to induce TEN
Management
Toxic epidermal necrolysis (TEN) is a potentially life-threatening skin disorder that is most commonly seen secondary to a drug reaction. In this condition the skin develops a scalded appearance over an extensive area. Some authors consider TEN to be the severe end of a spectrum of skin disorders which includes erythema multiforme and Stevens-Johnson syndrome
Features
systemically unwell e.g. pyrexia, tachycardic
positive Nikolsky’s sign: the epidermis separates with mild lateral pressure
Drugs known to induce TEN phenytoin sulphonamides allopurinol PENICILLINs carbamazepine NSAIDs
Management
Stop precipitating factor
supportive care, often in intensive care unit
Intravenous immunoglobulin has been shown to be effective and is now commonly used first-line
Other treatment options include: immunosuppressive agents (ciclosporin and cyclophosphamide), plasmapheresis
