Dermatology - Inflammatory Dermatoses Flashcards
Define atopic
A form of allergy in which a hypersensitivity reaction (e.g. eczema, asthma) may occur in a part of the body not in contact with the allergen.
These are IgE mediated reactions that trigger histamine release.
What is atopic eczema/dermatitis?
A chronic, atopic, inflammatory skin condition caused by defects in the normal continuity of the skin barrier, leading to inflammation in the skin.
What is the cause of atopic eczema?
Defects in the normal continuity of the skin barrier, leading to inflammation in the skin.
Tiny gaps in skin barrier provide an entrance for; irritants, microbes & allergens that create an immune response → associated symptoms.
Aetiology of eczema?
- Genetic component – mutation in filagin (leads to dry skin)
- Tends to run in families but there is no single inheritance pattern
- Atopic triad – eczema, asthma and hayfever
What are some aggravating factors for eczema?
- Stress
- Infection
- Dryness
- Allergy
Give 5 endogenous types of dermatitis
- Atopic
- Discord
- Pompholyx
- Gravitational
- Seborrhoeic
Give 3 exogenous types of dermatitis
- Irritant
- Allergic
- Photodermatitis
Prognosis of eczema?
Is a lifelong disease (chronic) but can be controlled with medications.
What is the diagnostic criteria for atopic eczema?
- Major criteria:
- Itchy skin condition (or reports or rubbing/scratching)
- Minor criteria:
- Onset <2 years
- History of skin crease involvement (includes cheeks)
- History of dry skin
- Personal or 1st degree relative history of atopic disease
- Visible flexural dermatitis
Give the typical presentation of atopic eczema (where on the body, what they look like)
Where → Flexor surfaces (insides of elbows, insides of knees)
Look: Dry, red, itchy and sore patches of skin
What potential viral skin infection are those with eczema at risk of?
Eczema Herpeticum
What is Eczema Herpeticum?
A viral skin infection in patients with eczema caused by the herpes simplex virus (HSV) or varicella zoster virus (VSV)
What virus is Eczema Herpeticum caused by?
Either a) VSV, b) HSV
Why are those with eczema more at risk of opportunistic bacterial infections?
The breakdown in the skin’s protective barrier allows an entry point for infective organisms
What is the most common pathogen causing opportunistic bacterial infections in those with eczema?
What is the treatment?
Pathogen → S. aureus
Treatment → Flucloxacillin
What environmental factors may affect eczema symptoms?
- Changes in temperature
- Certain dietary products
- Washing powders
- Cleaning products
- Emotional events or stresses
Give the stepwise treatment in the management of eczema & treatment of eczema flares
Management:
- Daily → Emollients
- Prevention of flares → Calcineurin inhibitors (e.g. tacrolimus ointment, pimecrolimus cream)
Treatment of flares:
- 1st line → Topical steroids (e.g. hydrocortisone is mildest, dermovate is strongest)
- Further treatments include: oral antibiotics for 2ary infection, oral steroids, oral immunosuppressants (e.g. methotrexate, azathioprine, ciclosporin)
Purpose of emollients?
To create an artificial barrier over the skin to compensate for the defective skin barrier
What activities should be avoided in eczema?
Avoid activities that break down the skin barrier: bathing in hot water, scratching or scrubbing their skin and using soaps and body washes that remove the natural oils in the skin
Difference between irritant contact and allergic contact dermatitis?
Irritant → Due to superficial damage of the skin surface
Allergic → Due to a substance or material in contact with the skin causing an allergic reaction.
Which type of dermatitis is often linked to occupation (e.g. soap)?
Irritant contact dermatitis - can be seen in hairdressers, nurses etc
Which type of dermatitis is often seen around mouths of children? Why?
Irritant contact - due to excessive licking or dribble (saliva is alkaline)
Why does superficial damage of the skin surface lead to irritant contact dermatitis?
- Due to damage of the skin surface by a substance or material, allowing deeper penetration of the irritant
- The extent depends on the irritant and amount/length/frequency of irritant exposure
What are common irritants for irritant contact dermatitis?
soaps, detergents, adhesives and friction caused by materials
Presentation of irritant contact dermatitis?
- Usually only present within the area of contact with the irritant
- Red itchy patch, can be well demarcated and dry
- May be swelling and blistering with severe reactions to strong irritants
Management of irritant contact dermatitis?
- Avoidance of irritant
- Emollients
- Topical steroids
What is most common cause of allergic contact dermatitis?
More common in women due to an allergy to nickel present in jewellery
What type of hypersensitivity reaction is allergic contact dermatitis?
Type 4 delayed - 48-72 hours to appear after exposure (delayed)
Treatment of allergic contact dermatitis?
- Identify the allergen and take avoidant measures
- Emollients
- Topical steroids
Presentation of allergic contact dermatitis?
- It may resolve on its own as long as the allergen is removed
- Usually only affects the area which had direct contact with the allergen but may spread
- Often red & itchy but can become swollen and develop blisters & fissures
How is allergic contact dermatitis confirmed?
By a patch test
What is a mild form of sebhorrhoeic dermatitis known as?
Dandruff
Cause of sebhorrhoeic dermatitis?
Due to an overgrowth of the yeast Malassezia
Which type of dermatitis often affects the lower legs of elderly patients?
Stasis dermatitis/venous eczema
Cause of stasis dermatitis?
Venous insufficiency - results in fluid pooling in the tissues of the leg, activating an immune response and leading to inflammation
Risk factors for stasis dermatitis?
- DVT
- Cellulitis
- Chronic leg swelling
- Varicose veins
- Venous leg ulcers
Which type of dermatitis presents with;
a) haemosiderin deposition
b) atrophie blanche
c) lipodermatosclerosis
d) ‘champagne bottle’ lower leg shape
Stasis dermatitis
Clinical features of stasis dermatitis
- Patches/plaques can be itchy, red and blistered or dry and scaly
- Haemosiderin deposition causes a brown discolouration
- Atrophie blanche – white patches of thin and scarred skin
- Lipodermatosclerosis – skin thickening
- ‘Champagne bottle’ lower leg shape
- 2ary infection can occur leading to cellulitis (S. pypgenes)
What type of dermatitis is often caused by and exacerbated by low humidity conditions and excess washing?
Asteatotic dermatitis
What is psoriasis?
A chronic, autoimmune, inflammatory skin condition that causes recurrent symptoms of psoriatic skin lesions.
Pathophysiology of psoriasis?
- T cells are inappropriately induced to produce cytokines that stimulate inflammatory cell infiltration (leading to erythema) and keratinocyte proliferation (leading to scale as the stratum corneum is shed from the skin)
- Skin changes caused by rapid regeneration of new skin cells – resulting in an abnormal buildup and thickening of skin in those areas
What causes the ‘scale’ seen in psoriasis?
Keratinocyte proliferation leads to scale as the stratum corneum is shed from the skin
What is the Auspitz sign?
Gentle scraping and removal of scale causes pinpoint capillary bleeding
What would an Auspitz’s sign potentially indicate?
Psoriasis
Give some precipitating factors for psoriasis
- Infections – streptococcal (associated with guttate psoriasis)
- Hormonal changes – e.g. postpartum
- Initiation, withdrawal or change in dose of some medications e.g. lithium, chloroquine and derivatives, and steroids (systemic & potent topical forms)
Which type of psoriasis is associated with a previous Strep infection?
Guttate
Give some exacerbating factors for psoriasis
- Trauma e.g. cuts, abrasions or sunburn – may precipitate spread of plaques to unaffected areas (Koebner phenomenon)
- Smoking
- Alcohol
- Some medications
- Psychological stress
What can be a relieving factor for psoriasis?
Sunlight
Describe the typical presentation of psoriatic lesions
- Typically found on extensor surfaces - normally scalp, elbows and knees
- Red (erythematous)
- Scaly plaques (areas of thickened skin)
What other symptoms/signs may psoriasis present with?
- Nail changes - pitting, onycholysis
- Joint pain and stiffness (psoriatic arthritis)
What is the most common type of psoriasis?
Chronic plaque psoriasis (90%)
How does guttate psoriasis present?
Multiple small, scaly plaques distributed across the trunk and limbs which may resemble raindrops
What is a rare but severe form of psoriasis that can lead to widespread inflammation?
Erythrodermic psoriasis
Give some conditions associated with psoriasis
- Psoriatic arthritis
- IBD - psoriasis can be a cutaneous manifestation of IBD
- Uveitis - inflammation of mid portion of eye
- Nail psoriasis
- Metabolic syndrome - abdominal obesity, hypertension & insulin resistance
- Poor mental health resistance
What lifestyle advice can be given to psoriasis patients?
- Avoiding exacerbating factors
- Smoking cessation
- Reducing alcohol
- Maintaining healthy weight
Describe the stepwise in the management and treatment of psoriasis
Daily → Emollients
Treatment of inflammation:
- 1st line → topical corticosteroids
- 2nd line → topical calcineurin inhibitors
More severe treatments:
- Oral retinoids e.g. Acitretin
- Oral immunosuppressants e.g. ciclosporin, methotrexate
- Vitamin D analogues (e.g. Cacipotriol)
Which oral retinoid can be used in the treatment of psoriasis?
Acitretin
What is phototherapy used to treat?
Eczema and psoriasis that doesn’t respond to other treatments
What is the pilosebaceous unit?
- Consists of the hair shaft, the hair follicle, the sebaceous gland, and the erector pili muscle. These units are found everywhere on the body except the palms, soles, top of feet, and lower lip.
Define acne vulgaris
A disorder of the pilosebaceous unit characterised by pustules, papules and comedones.
How do androgens play a role in acne?
Androgens drive sebum production from the sebaceous glands (this is why acne is exacerbated by puberty and improves with anti-adrenergic hormonal contraception)
Pathophysiology of acne?
Increased sebum + trapping of keratin (dead skin cells) → blockage of pilosebaceous unit → swelling and inflammation (comedones)
Which bacteria is thought to be involved in acne?
Propionibacterium acnes (P. acnes)
Other hormonal imbalances lead to excess androgens that can drive acne. Name 2 conditions that cause excess endogenous androgens
PCOS (polycystic ovarian syndrome)
Congenital adrenal hyperplasia
Name two exogenous causes of excess androgens (that can lead to acne)?
Steroids
Testosterone
A diet high in what has an association with acne?
high glycaemic index foods
Open vs closed comedone?
- Closed comedones – a blocked hair follicle covered by skin (whitehead)
- Open comedones – a blocked hair follicle not covered by skin (blackhead)
Clinical presentation of acne?
- Seborrhoea
- Closed / open comedones
- Papules
- Pustules
- Nodules
- Cysts
- Scarring
Papule vs pustule?
- Papules – small (<1cm), elevated, solid inflammatory lesions that appear erythematous
- Pustules – small, well-circumscribed, erythematous epidermal lesions filled with pus (‘pimple’)
Nodule vs papule?
Nodules are >1cm in size
What is keloid scarring?
shiny, rubbery nodules of fibrous scar tissue, which may be larger than the original lesion
What is the most common endocrinopathy in women?
PCOS
How does PCOS affect acne?
Leads to increased thecal ovarian androgen production and a reduction in sex-hormone-binding protein leading to an increase in free androgens (exacerbate acne)
What are the 3 main aims of management of acne?
- Reduce symptoms
- Reduce risk of scarring
- Minimise psychosocial burden
Give the stepwise process in the management of acne
- Lifestyle advice - diet, non-comedogenic products
- Topical salicylic acid
- Topical benzoyl peroxide
- Topical retinoids
- Topical antibiotics
- Oral antibiotics
- Spironolactone
- Oral retinoids
What is the most common oral retinoid used in the treatment of acne?
Isotretinoin (Roaccutane)
What is the mechanism of isotretinoin?
Targets different factors that cause acne including the production of sebum and production of keratin (outer scales of skin) that block the pores of the hair follicle.
When would isotretinoin be prescribed?
Last line option in severe acne
Contraindications for isotretinoin?
- Pregnancy & breastfeeding → teratogenic (women must be put on pregnancy prevention programme)
- Soya/peanut allergy
- Mental health conditions → link between suicide and isotretinoin
Side effects of isotretinoin?
- Dryness of skin, lips and eyes (most common)
- Skin infections
- Increased sensitivity to sun
- Teratogenic
- Liver inflammation
Function of salicylic acid in acne?
SA is a keratolytic that unblocks pores by removing keratin plugs
How does benzoyl peroxide work in the treatment of acne?
Reduces inflammation, helps unblock skin and is toxic to P, acnes bacteria (antibacterial effects)
Side effects of benzoyl peroxide?
Bleaching or irritation of skin
What is the most commonly prescribed topical retinoid in the treatment of acne?
Adapalene
What are the ingredients in Epiduo for acne?
Adapalene (topical retinoid) + benzoyl peroxide
Side effects of topical retinoids?
irritation, photosensitivity, teratogenic (women of childbearing age need effective contraception)
What is the most common antimicrobial used in the treatment of acne vulgaris?
Erythromycin & clindamycin
What are the ingredients in Duac for acne?
Clindamycin + benzoyl peroxide
How are topical antibiotics useful in the management of acne?
Used for anti-inflammatory properties (in low doses) rather than antibacterial effects
Which 2 oral antibiotics are most commonly used in the treatment of acne?
Doxycycline, lymecycline
How does the oral contraceptive pill help in the treatment of acne?
Can stabilise hormones and slow production of sebum through anti-adrenergic properties (Co-cyprindiol / Dianette) is most effective) BUT can take up to 6 months to work.
How is spironolactone effective in the treatment of acne?
Anti-androgen
Contraindications of spironolactone for acne?
Pregnancy
Hypotension
What is rosacea?
A common, chronic skin condition causing flushing of the forehead, nose, cheeks, and chin. Flushing can be transient, recurrent or persistent.
What age group does rosacea typically affect?
30-60
Who is rosacea most common in ?
- Most common in those with pale skin
- Affects females more commonly than males (but can affect males more severely)
Risk factors for rosacea?
- Can be exacerbated by factors causing facial flushing:
- Sun exposure
- Hot weather
- Warm baths
- Stress
- Spicy foods
What is the clinical presentation of rosacea?
- Red rash over sun exposed sites - mainly central face, chest
- Can have different phenotypes:
- Erythema & telangiectasis
- Papules & pustules
- Rhinophyma
- Ocular involvement
Does rosacea involve comedones?
No
What is telangiectasis?
dilated, superficial, small blood vessels
What is rhinophyma?
Skin thickening, enlargement, and disfiguration of nose
How can rosacea affect the eyes?
blepharitis, conjunctivitis or keratitis
What general measures can be taken in the management of rosacea?
- Camouflage creams
- Sun protection
- Avoiding factors causing flushing
What topical treatments can be used in the management of rosacea?
- Suncream
- Azelaic acid
- Brimonidine gel (mirvaso gel)
- Ivermectin 1% (Soolantra)
- Emollients
- Topical antibiotics e.g. Metronidazole
What virus is chickenpox caused by?
Varicella zoster virus (VSV)
How common is chickenpox?
Over 75% of children are infected with VZV before age 5.
How is chickenpox transmitted?
Highly contagious. Droplet spread or direct skin contact with vesicle fluid, with the virus entering the body via the URT.
Incubation period of chickenpox?
10-14 days but can be up to 21 days.
Contagious period of chickenpox?
Chickenpox is contagious 1-2 days before rash appears until blisters have scabbed over (5-10 days).
Chickenpox typically presents initially with a prodrome. How may this present?
- Fever (38-39)
- General malasia
- Myalgia
- Anorexia
- Headache
- Nausea
Describe the rash classically seen in chickenpox
- Begins as small, erythematous macules on the scalp, face, trunk, and proximal limbs
- These macules develop into papules, vesicles and pustules which appear in crops
- Vesicles and pustules crust over
What is the management of chickenpox?
Often only symptomatic therapy is required:
- Hydration
- Avoidance of scratching
- Paracetamol
- Sedating antihistamines (e.g. chlorphenamine)
- Emollients & calamine lotion for itch
- Avoidance of pregnant women, immunocompromised and neonates
Why should NSAIDs be avoided in chickenpox?
NSAIDS should be AVOIDED as they increase risk of necrotising soft tissue infections.
Which cases require pharmacological treatment of chickenpox?
- High risk groups: neonates, pregnant women, immunosuppressed
- Treatment of 2ary bacterial skin infections with Abx
Which drug is used in treatment of chickenpox?
Oral aciclovir
Give some differentials for chickenpox
- HSV
- Shingles
- Hand, foot and mouth disease (Coxsackie A virus)
- Impetigo
- Scabies
- Dermatitis
Potential complications of chicken pox? (N.B. is usually self-limiting)
- Scarring
- 2ary bacterial infection
Complications in high-risk groups:
- Bacterial superinfection (infection on top of chickenpox lesions)
- Dehydration
- Conjunctival lesions
- Pneumonia
- Encephalitis (presents as ataxia)
- Reye’s syndrome – rare complication seen in children and young adults recovering from viral illness and though t to be related to aspirin use (AVOID IN CHILDREN)
- Disseminated varicella infection – high morbidity
- Thrombocytopenia & purpura
- Premature labour
What is Reye’s syndrome? What is it thought to be related to?
A rare but serious condition that causes swelling in the liver and brain. Most often affects children and teenagers recovering from a viral infection, most commonly the flu or chickenpox.
Thought to to be related to aspirin use (AVOID IN CHILDREN).
What type of reaction is erythema multiforme?
Erythema multiforme (EM) is a type IV hypersensitivity reaction which presents with a skin rash.
Erythema multiforme has two forms. What are these? How do they differ?
Minor & major
The major form includes mucosal involvement of at least one site (e.g. oral mucosa).
What is erythema multiforme most commonly caused by?
HSV infection
What is the defining feature of erythema multiforme?
Target shaped lesions
Where do the target lesions in erythema multiforme typically appear?
Target-like lesions appear on the hands and feet and progress proximally
What is the management of erythema multiforme?
Most cases require no treatment as the condition is self-limiting. If EM develops 2ary to an infective cause, this should be treated.
- Pharmacological:
- Aciclovir → treat HSV
- Doxycycline → treat mycoplasma infections
What is the dermatological manifestation of coeliac disease?
Dermatitis herpetiformis
What is erythema nodosum?
Erythema nodosum is a type of panniculitis, an inflammatory disorder affecting subcutaneous fat.
How does erythema nodosum present?
It presents as tender red nodules on the anterior shins.
What inflammatory condition is associated with erythema nodosum?
IBD
What is the most common cause of erythema nodosum?
Beta-haemolytic streptococcal infections
