Dermatology 1 (inflammatory) Flashcards
What are the functions of the skin?
- Physical barrier
- Thermoregulation
- Fluid balance
- Vitamin D synthesis
- Sensation
What is the outer layer of the skin called and what cells are in it?
Epidermis
Keratinocytes (90%) and melanocytes
What are the layers of the epidermis?
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
Define macule and papule
Macule = small, flat lesion <5mm Papule = small, raised lesion <5mm
Define nodule and patch
Nodule = discrete raised lesion >1cm Patch = diffuse flat lesion >1cm
Define vesicle, bulla and pustule
Vesicle = small fluid filled lesion <5mm Bulla = large fluid filled lesion Pustule = pus filled blister <5mm
What is telangiectasia?
Dilated blood vessels visible on the skin
Difference between erosion and ulcer
Erosion = superficial Ulcer = deep
When describing a skin lesion, what is the structure you follow?
- Site
- Size
- Shape, symmetry and border
- Colour + pigmentation
- Surface features
- Surrounding skin
What is the distribution of eczema?
Flexor surfaces
What is the diagnostic criteria for atopic eczema?
Itchy skin condition plus 3 of the following:
- History of itchiness in skin creases
- History of atopic disease
- General dry skin
- Visible flexural eczema
- Onset in first 2 years of life
What are the first line treatments for eczema?
Emollients (500g per week in adults) - creams, lotions, ointments, soap substitutes
Topical steroids - hydrocortisone (mildest) to dermovate (most potent)
How much does 1 finger tip unit cover?
2 palms of area
What are some complications of eczema?
Lichenification in adults
Staphylococcal infection
Eczema herpeticum = rapidly worsening, painful, clustered blisters and punched out erosions
How would you treat an infection of eczema?
Flucloxacillin for 14 days (erythromycin if penicillin allergic)
What genetic mutation is associated with atopic eczema?
Filaggrin
Where and how does discoid eczema present?
Symmetrical oval erythematous patches/plaques on extremities
Extremely itchy especially at night
What age is discoid eczema more common in?
Over 60 years old
What type of hypersensitivity reaction is allergic contact dermatitis?
Type IV hypersensitivity - occurs after sensitisation and re-exposure to allergen
How can you distinguish between irritant and allergic contact dermatitis?
Irritant = fast onset of burning, stinging, soreness in exposed area and resolves quickly after removal of irritant
Allergic = delayed onset of redness, itch, scaling in exposed area and other areas. Takes longer to resolve.
Which type of contact dermatitis is more commonly associated with atopic eczema?
Irritant contact dermatitis
What are the main risk factors for seborrhoeic dermatitis?
Immunocompromised
Stress and fatigue
Parkinson’s
What causes seborrhoeic dermatitis?
Inflammatory reaction to yeast (Malassezia spp) due to reduced resistance to the yeast
How does seborrhoeic dermatitis present?
Erythematous scaling rash over nasolabial folds, bridge of nose, eyebrows, ears and scalp (dandruff)
What medication can you give for seborrhoeic dermatitis?
Ketoconazole = topical antifungal
What can you use to remove crusts on the skin?
Salicylic acid and olive oil
How is acne rosacea different to seborrhoeic dermatitis?
It is not scaly
It spares the nasolabial folds
It has papules and pustules
What bacteria can cause infection in acne vulgaris?
Propionibacterium Acnes
What is acne vulgaris a disorder of?
Pilosebaceous follicles
What can acne vulgaris be associated with?
Excess androgens e.g:
- Polycystic ovarian syndrome
- Cushing’s
- Steroid abuse
How do you treat mild and severe acne vulgaris?
Mild - benzoyl peroxide
Severe - retinoids
What are the side effects of retinoids?
Teratogenic - don’t give in pregnancy
Photosensitivity
Dry skin
What antibiotics are useful in acne vulgaris
Doxycycline/tetracycline
What is acne rosacea?
Chronic, relapsing erythema/flushing, telangiectasia, papules and pustules affecting the face
What ocular symptoms are associated with acne rosacea?
Blepharitis
Conjunctivitis
Stinging of eyes
What do men especially get with acne rosacea?
Rhinophyma = large nose
What kinds of things can trigger acne rosacea?
Temperature changes Alcohol Caffeine Spicy foods Stress Amiodarone
What is the management for mild and severe acne rosacea?
Mild = topical metronidazole or azelaic acid Severe = oral tetracycline/erythromycin
What causes urticaria?
Food/drugs/insect bites/infections cause increased permeability of capillaries (histamine-mediated) which leads to itchy white weals with erythematous flare
What is the treatment for urticaria?
Antihistamines e.g. loratidine
What can be a complication of urticaria and how do you manage it?
Angio-oedema (non-pitting facial erythematous oedema) which can lead to airway obstruction and anaphylaxis
Treat with adrenaline, oxygen, hydrocortisone, chlorphenamine (antihistamine)
What is the pathophysiology behind psoriasis?
Inflammatory autoimmune T-cell mediated
How does chronic plaque psoriasis present?
Extensor surfaces, scalp and lower back
Itchy circular symmetrical erythematous plaques with fissuring
What is Auspitz’ sign?
Bleeding on scraping of a psoriatic lesion
What is Kobner’s reaction? What conditions demonstrate this reaction?
Lesions arising following trauma to skin in otherwise health skin
- Psoriasis
- Lichen planus
- Vitiligo
What nail changes are seen in psoriasis?
Pitting - superficial depressions in nailbed
Onycholysis - separation of nail plate from nailbed
Subungual hyperkeratosis - thickening of nailbed
Oil drop discolouration
What triggers a relapse of psoriasis?
· Skin trauma (Koebner phenomenon) · Infection - strep, HIV · Drugs - BALI - Beta-blockers - Anti-malarials - Lithium - Indomethacin/NSAIDs · Withdrawal of steroids · Stress · Alcohol and smoking · Cold/dry weather
What antigens is psoriatic arthritis associated with?
HLA-B27 (also ankylosing spondylitis, IBD, reactive arthritis)
HLA-DR4 (also RA and type 1 diabetes)
What topical treatments are used for psoriasis?
Emollients
Topical vitamin D - reduces keratinocyte proliferaiton
Potent topical steroids (betnovate)
What DMARDs can be given for psoriasis?
First-line - Methotrexate
Second-line - Ciclosporin (1st line if rapid disease control needing or are considering conception)
Third-line - Acitretin
What areas are most commonly affected by lichen planus?
Flexors
Genitalia
Mucous membranes
What is the pathophysiology of lichen planus?
T-cell mediated autoimmune condition where the inflammatory cells attack a protein within the skin and mucosa
How does lichen planus present?
Itchy eruptions of papules and polygonal plaques that look like white lace
Wickham’s striae = white on buccal mucosa
What disease is lichen planus associated with?
Hepatitis C
What is a potential complication of oral lesions in lichen planus?
2% malignant potential to squamous cell carcinoma
What conditions is lichen sclerosis associated with?
Thyroid diseases
Diabetes
What is the treatment for lichen planus?
Potent topical steroids e.g. dermovate
What is the management of eczema herpeticum?
Oral acyclovir
Oral flucloxacillin (to cover secondary bacterial infection)
Stop topical steroids
What are the 5 different types of psoriasis?
- Chronic plaque psoriasis
- Flexural (inverse) psoriasis
- Guttate psoriasis
- Pustular psoriasis
- Generalised/erythrodermic psoriasis
How does guttate psoriasis present and what usually causes it?
Multiple small, tear-drop shaped, erythematous plaques occurring on the trunk
Post-Strep infection in young adults
How does pustular psoriasis present?
Multiple petechiae and pustules on palms and soles
What phototherapy is used to treat psoriasis?
- Narrowband UVB phototherapy
2. Psoralen + UVA (PUVA)
What are the side effects of ciclosporin?
5 H’s
- Hypertrophy of gums
- Hypertrichosis
- Hypertension
- Hyperkalaemia
- Hyperglycaemia (diabetes)
Requires monitoring of U&Es, BP and fasting glucose
