PBL 2 Flashcards
What are excoriations?
destruction and removal of skin surfaces caused by scratching = lesions
what is a naevus?
a birthmark or mole on the skin
what are the 7 types of eczema?
Atopic dermatitis Contact dermatitis Dyshidrotic eczema neurodermatitis nummular eczema seborrheic dermatitis stasis dermatitis
What causes contact dermatitis?
when the skin becomes irritates or inflamed after coming into contact with a substance that triggers an allergic reaction e..g soap or hair dyes
what are the 2 types of contact dermatitis?
irritant contact dermatitis and allergic contact dermatitis
what’s the main difference in pathology between irritant and allergic contact dermatitis??
Irritant contact dermatitis is a nonspecific response of the skin to direct chemical damage
while allergic contact dermatitis is a delayed hypersensitivity reaction to exogenous contact antigens
what are the symptoms of contact dermatitis?
inflamed, blistered, dry, thickened and cracked skin- most often on hands and face
What causes dyshidrotic eczema?
A reaction to something that has touched your skin. Commonly nickel, detergents, soap, perfume, sweat.
what are the symptoms of dyshidrotic eczema?
itching/burning pain before blisters appear
blisters on edges of fingers of toes, soles of feet and palms of hands
red cracked skin
sweaty skin
nails that thicken and change colour
what’s the cause of neurodermatitis?
cause isn’t known but some triggers may include tight clothing, bug bites etc (something that irritates the skin)
what are the symptoms of neurodermatitis?
intense itching confined to a specific patch of skin. Over time the scratching can cause lichenified skin.
what’s the cause of nummular eczema?
triggers may include very dry or sensitive skin and trauma from insect bites, scrapes or chemical burns.
what are the symptoms of nummular eczema?
tiny bumps and blister-like sores
coin-shaped raised spots
spots of variable colour
itchy/dry skin
when we find nummular eczema on the legs, what can we link it to?
stasis dermatitis - probably caused by poor blood flow
what are the symptoms of seborrheic dermatitis?
scaly, greasy patches on scalp, upper back and nose
dandruff
what is the cause of seborrheic dermatitis?
An inflammatory reaction to excess Malassezia yeast, an organism that normally lives on the skin’s surface
what is the cause of stasis dermatitis/varicole eczema?
when varicose veins or other circulatory conditions cause fluids to build up in the lower legs.
what are the symptoms of stasis dermatitis?
ankle swelling orange-brown speckles of discolouration itching scaling redness dryness sores that ooze hair loss on ankles or shins varicose veins
what is the most common form of eczema?
atopic dermatitis
where does atopic dermatitis appear in different age groups?
infants - scalp and face (cheeks)
children - flexor surfaces of extremities, face and scalp
adults - hands, neck, flexor surfaces, feet, around eyes
what type of reaction is atopic dermatitis?
a type 1 hypersensitivity reaction
Outline the sensitisation stage of the pathophysiology of atopic dermatitis?
an allergen travels through the slightly-porous skin and is picked up by an APC which presents the antigen to a naive T cell causing it to mature into a T helper 2 cell. This cell can then activate a B cell which can begin to produce IgE specifc to the pollen. The IgE antibodies bind to mast cells and basophils
Outline the second exposure of allergen stage of the pathophysiology of atopic dermatitis?
the allergen can cross-link the IgE antibodies on the mast cells/basophils, resulting in the degranulation of pro-inflammatory molecules. This causes nearby blood vessels to dilate and become leaky, attract more immune cells to the area = inflammation of the skin tissue.
Overall, this makes the skin tissue more leaky, letting in more allergen and more water to escape = dry, scaly skin.
outline the atopic dermatitis cycle of symptoms?
allergy-mediated inflammation causes dry skin which causes itching which makes the skin more porous, letting in more allergen and out more water = more allergy-mediated inflammation
how does skin become lichenified in atopic dermatitis?
through prolonged scratching and rubbing causing cell growth
what’s the cause of most atopic dermatitis in children?
Mutations in the filaggrin gene greatly reduce the amount of filaggrin protein in the skin or lead to its complete absence resulting in cracks in the skin barrier that expose the lower layers to allergens which are usually kept out, thus causing eczema
what are common triggers for eczema?
cigarette smoke mould dust mites changes in weather stress wools detergents chemicals pet danger
what is the atopic triad?
atopic dermatitis
allergic rhinitis
asthma
what’s the role of filaggrin?
It brings together structural proteins in the outermost skin cells to form tight bundles, flattening and strengthening the cells to create a strong barrier.
what are the treatment options for eczema?
identifying and avoiding triggers avoiding overheating dietary changes dressing in soft fabric managing stress frequent moisturising after warm baths keeping finger nails short topical corticosteroids Calcineurin inhibitors antihistamines antibiotics
what are some complications of eczema?
skin infects - weeping eczema
psychological effects e.g. bullying, self confidence knocks and problems sleeping
what is eczema herpticum?
when eczema becomes infected with the herpes simplex virus - potentially life threatening
what are some mild topical steroid options for eczema?
hydrocortisone and clobetasone