Skin Conditions Flashcards
What is psoriasis?
Autoimmune disease mediated by T-lymphocytes = vascular + inflammatory changes
Where is psoriasis common?
Head
Knees
Elbows
What factors aggravate psoriasis?
Stress
Excessive alcohol consumption
Smoking
Who is psoriasis common in?
Adults
What is psoriasis thought to be?
Hereditary
What is psoriasis characterised by?
Thick, silvery scales
Who is eczema common in?
Children
What is eczema thought to be?
Environmental
What is eczema characterised by?
Red, inflamed skin
What can eczema be called?
Atopic dermatitis
What are the signs + symptoms of eczema?
Red, scaly
Extremely dry
Affect flexures
Vesicles + weeping
Excoriation + thickening of skin
What is eczema?
Nonspecific term that refers to group of inflammatory skin conditions characterised by pruritis (itching), erythema (red swelling) + scale
What is dermatitis?
Chronic, relapsing inflammation of skin
Broader term than eczema
What may be the causes of AD?
Allergy
Irritant
Photodermatitis (sunlight)
What is the pathogenesis of AD?
Multifactorial
Combo of genetic + environmental factors
What factors play a role in the pathogenesis of AD?
Genetics
Skin barrier dysfunction
Impaired immune response
Environment
What is the filaggrin gene?
Genetic factors of AD
Synthesis of a protein that holds the integrity of skin barrier
How many mutations is there of the filaggrin gene?
20
What are the environmental factors of AD?
Western lifestyle = low exposure to pathogens
Duration of breastfeeding = decreases risk
High social position of parents = in creased risk
What are the 2 hypotheses that have been proposed for pathophysiology of AD?
Immunological
Skin barrier
What is the immunological pathogenesis for AD?
Results from imbalance of T cells
Th2 predominates + leads to increased production of interleukins
= increased level of IgE + Th1
How many types of hypersensitivity reacts are there?
4
What is the timing of Type I hypersensitivity reaction?
30 mins
What is the antigen of Type I hypersensitivity reaction?
Induces IgE response
What is the timing of Type II hypersensitivity reaction?
Mins to hours
What is the antigen of Type II hypersensitivity reaction?
On cell surface
What is the timing of Type III hypersensitivity reaction?
3-8hrs
What is the antigen of Type III hypersensitivity reaction?
Extracellular-soluble
What is the timing of Type IV hypersensitivity reaction?
48-72hrs
What is the antigen of Type IV hypersensitivity reaction?
Induces T-cell
What is the skin’s functions?
Regulates body temp
Stores blood
Protects body from external environment
Detects cutaneous sensations
Excretes + absorbs substances
Synthesises vit D
What are the 3 layers of the skin?
Epidermis
Dermis
Hypodermis
What is the function of the epidermis?
Thin layer of dead cells
Defence against outside world
What is the function of the dermis?
Made of collagen fibres
Keeps skin strong + flexible
Houses network of blood vessels = keeps our body temp constant despite external changes
What is the function of the hypodermis?
Body fat is stored
= energy, sweat glands + new skin manufactured to repair cuts
What are the 5 layers of epidermis?
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
Describe filaggrin
Helps bind keratinocytes together = intact barrier hydrated stratum corneum
Mutation = less filaggrin
Itch = impairment of skin
What are the 4 things that play into pathogenesis of pruritus?
Barrier dysfunction
Environmental factors
Immunological factors
Pruritus
What is involved in barrier dysfunction?
Ceramide reduction = H2O retention = dry
Over-desquamation = over-shredding
Filaggrin deficiency
What is involved in the immunological factors?
Th2 cells
Th17 cells
Eosinophils
Mast cells
What is involved in environmental factors?
Climate
Smoking
Skin pH
Microbiome
What can the skin be irritated by?
Soap
Detergents
Wool clothing
Hot weather
Emotional stress
Exposure to triggers
Where is AD most common in infants?
Face first
Then hands + feet
Where is AD most common in older children?
Skin folds (elbows, behind knees)
Where is AD most common in adults?
Face + hands
What are the side effects of steroids?
Weight gain
Osteoporosis
Think skin
Psychosis
What are the aims of treatment for AD?
Treat + control symptoms - eg. itching, pain + discomfort
Reduce inflammation
Reduce lost moisture
Inhibit scratching = decrease infection
Improve QoL
What are the different treatments for AD?
Reduce contact with irritants (soap substitutes)
Identify + reduce exposure to allergen
Emollients
Topical steroids
Antihistamines
Antibiotics
Systemic steroids
Other (herbal/soaps)
How do you reduce contact with irritants?
Avoid overheating
Avoid direct skin contact with rough fibres
Avoid dusty conditions
Avoid cosmetics
Avoid soap
Use gloves to handle chemicals
What do emollients do?
Hydrate + soften skin
= restore/replace epidermal barrier
= protection against pathogen bacterial colonisation
What do topical steroids/steroids do?
Up-regulates the expression of anti-inflammatory proteins
+ represses the expression of proinflammatory proteins in cytosol
= prevents translocation of transcription factors
What do antihistamines do?
Antagonists acting via histamine H1 receptor
What do antibiotics do?
Anti-bacterial properties
What are the 4 major components of AD treatment?
Anti-inflammatory
Anti-pruritic
Moisturiser
Anti-bacterial
What treatments should be used initially?
Topical skin applications
What are ointments for?
Very dry skin
What are the properties of ointments?
Greases
Occlusive
What are pastes?
Ointment suspensions
Application of noxious chemicals for localised delivery
What are creams for?
Less dry skin
What are the properties of creams?
Emulsions
Quick absorption
What are lotions for?
Less dry skin
What are the properties of lotions?
Less messy on wet/hairy surfaces
Cooling effect
What are the properties of gels?
Hydrophilic/hydrophobic
High H2O content
What are the properties of emollients?
Hydrophobic
Paraffin derivatives
Aq. cream alternative
What should be used of a corticosteroid ointment if used long term?
Low-potency
= decreases risk of side effects
What is tachyphylaxis?
More used = daily = less effective
= change to weekly = can use longer
Even if dose increased wont change the effectiveness
What are calcineurin inhibitors?
Steroid free alternative
What is an example of calcineurin inhibitors?
Pimecrolimus
What are the side effects of calcineurin inhibitors?
Local burning
Skin malignancy
Infection risk
What are tar band properties?
Anti-inflammatory + anti-pruritic
What is phototherapy?
Narrow-band UVB
What is the aim when using emollients?
To reduce skin H2O loss = protective film
What should emollients be used instead of?
Soap
Add to bath water/use in shower
How do you use emollients?
Use all the time not just with symptoms
Large amount at least BD
Use after bath/shower
Pat dry skin + apply whilst skin is moist
Smooth onto skin = do NOT rub
Use spoon/pump dispenser
Never share
What are the different strengths of topical CCS?
Very mild = hydrocortisone
Moderate = clobetasone
Strong = mometasone
Should be prescribed weakest effective treatment to control symptoms
How do you use topical CCS?
OD/BD for 1-2 weeks
Affected areas
Smooth onto skin in direction of hair growth
Use emollients first the 30mins later = CCS
What is FTU?
Fingertip units
500mg amount required to squeeze a line from tip of adult finger to crease
How much topical CCS should be used?
1 FTU to treat area of skin size of two palms
What are the side effects of topical CCS?
Burning/stinging = improves with use
Less common = inflamed hair follicles, thinning of skin, contact dermatitis, acne + changes in skin colour
What are examples of systemic therapy?
Sedative antihistamines = help sleep
Immunosuppressant = resistant/rapid relapse
Antibacterials = secondary infection
What is the treatment for contact dermatitis?
Barrier to irritant
Dilute topical CCS
Potassium permanganate soaks
