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
what are some moderately potent topical steroid options for eczema?
betamthasone validate and triamcinolone
what are some potent topical steroids used for eczema?
high doses of betamethasone validate and betamethasone dipropionate
what are some very potent topical steroid options for eczema?
clobetasol propionate and diflucortolone valerate
what’s the risks with high potency topical steroids?
greater risk of side effects
how do we measure the amount of topical steroid that you should apply?
by finger tip units (FTU)
how do we decide which potency of topical steroids we should prescribe?
use the lowest-strength first and if there’s no improvement in 3-7 days then use a stronger one. Sometimes a very potent steroid is used from the outset if the eczema is very severe
what are some potential side effects of topical steroids for eczema?
stinging or burning when applying thinning of skin permanent stretch marks bruishing discolouration telangiectasias skin colour changes hair may grow more skin peeling
what are some serious concerns when prescribing long term use of topical steroids for eczema?
Cushing’s syndrome
the effect on growth
what is the mechanism of action of topical corticosteroids?
They bind to glucocorticoid receptors within skin cells and WBCs, ultimately decreasing production of inflammatory mediator molecules and increasing the production of anti-inflammatory molecules. They also cause local vasoconstriction of cutaneous blood vessels which also reduce inflammation.
What is the pathophysiology of melanoma?
UV light and genetic susceptibility causes an accumulation of genetic mutations in melanocytes which activates oncogenes, inactivates tumour suppressor genes and impairs DNA repair. This leads to melanocyte proliferation, blood vessel growth, tumour invasion, evasion of the immune response and metastasis.
outline the clark model of melanoma?
level 1 - melanoma cells in epidermis only
Level 2 - melanoma cells extend into papillary dermis
Level 3 - melanoma cells extend to border of reticular dermis
level 4 - melanoma cells extend into reticular dermis
level 5 - melanoma cells grow into subcutaneous fat
what are some risk factors for melanoma?
family history personal history fitzpatrick types 1 and 2 (light skin, hair and eyes) history of severe sunburn intermittent intense sun exposure immunosuppression having many naevia Older age being Caucasion
why is having a family history of melanoma a risk factor?
because 25-50% of people with hereditary melanoma have a mutation in the CDKN2A tumour suppressor gene leading to uncontrolled melanocyte proliferation
why is being fitzpatrick type 1 or 2 a risk factor for melanoma?
80% of these groups carry germline variations in the melanocortin receptor 1 gene which impairs the production of melanin and instead they produce pheomelanin which has no UVB protection
Explain what it means when melanoma is described as immunogenic?
a healthy immune system generates a strong immune response to melanoma cells
what is the typical presentation of melanoma?
a pigmented lesion which is asymmetric, has ill-defined borders, bleeds and ulcerates
what are the 4 main types of melanoma?
superficial spreading
nodular
lentigo maligna
acral lentiginous
outline the key features of superficial spreading melanoma?
a lesion of variable colour that grows horizontally very slowly before moving into deeper layers of the skin. Commonly ulcerates and bleeds.
Seen mostly on legs of women and backs of men
what causes superficial spreading, nodular and lentigo maligna melanomas?
intermittent high intensity UV exposure
does sun exposure cause acral lentiginous melanoma?
no
what are the key features of nodular melanoma?
a changing, usually black, lump on the skin mostly on the chest/back/head/neck that is dark blue or bluish-red. It grows rapidly down into layers of skin and metastasises
most aggressive form of melanoma!!
what are the key features of lentigo maligna melanoma?
large, flat, slow growing brown->black lesions that develop horizontally over many years and may grown vertically eventually. Often seen on face/arms/back (areas which are often exposed to the sun)
what are the key features of acral lentiginous melanoma?
fast growing and variably coloured
more common in those with darker skin
Often seen on palms, soles or under nails
RARE
when examining melanomas, what do we look for?
Assymetry Border irregularity Colour variation Diameter >6mm Evolution
what are incisional biopsies?
a small cut (incision) is made into an area of abnormal tissue and a small piece of it is removed from the body and sent to labs
what is an excision biopsy?
A surgical procedure in which a cut is made through the skin to remove an entire lump or suspicious area so it can be checked under a microscope for signs of disease.
how can we prevent melanomas?
wearing protecting clothing e.g. long sleeves and hats
using sunscreen
sensible sun exposure
avoiding sunbeds
having regular self and doctor skin checks
what’s the treatment for melanoma?
complete excision if caught early regional lymph node removal is risk of recurrence is high immunotherapy chemotherapy radiation therapy
what is the ‘sentinel’ lymph node?
the first lymph node to which cancer cells are most likely to spread from a primary tumour
which groups of people is melanoma most common in?
caucasians over 65
where do we see the highest rates of melanoma in the world?
Australia and New Zealand - lots of caucasians in a place with high UVB
how common is melanoma?
the 5th most common cancer in the UK
the most common cancer in young adults
what are 5 ways in which cancer can spread?
hematogenously - through blood vessels through lymphatic system along nerve fibres transcoelomically - through body walls through needles/surgical instruments during medical procedures
what are primary and secondary tumours?
the primary tumour is the first tumour in thr body
the secondary tumour is the one formed from metastasis
note they are the same type of tumour
why is angiogenesis and lymphangiogenesis important in metastasis?
the proliferation of cells depends on an adequate supply of oxygen and nutrients and the removal of waste products
describe TNM staging
it looks at the size and extent of primary tumour
number of nearby lymph nodes that have cancer
and whether the tumour has metastasised
What does TxNxMx mean?
primary tumour cant be measured, cancer in nearby lymph nodes cant be measured and metastasis cant be measured
what does T0N0M0 mean?
primary tumour cant be found, no cancer in nearby lymph nodes and no metastasis
what does T1-4 mean in TNM staging?
how do we break this down further?
refers to the size of tumour e.g. T3 means the tumours between 2-3mm
T1a= tumour <0.8mm
T1b= tumour between 0.8 and 1 mm
T2-4 can be split into a and b too but this shows whether the tumour has ulcerated or not. B = ulcerated
what is an ulcerating tumour?
when a cancer that is growing under the skin breaks through the skin and creates a wound
what does N1-3 means in TNM staging?
Number and location of lymph nodes containing cancer
what does M1 in TNM staging mean?
the cancer has metastasised
what is the mitotic rate of melanoma?
the number of cells dividing in a certain amount of melanoma tissue. The higher the mitotic rate, the greater at risk the melanoma is of spreading.
what does Breslow’s depth tell us?
a measurement from the granular layer of the epidermis down to the deepest point of invasion
(measures depth of tumour)
what’s the 5 year survival rate if the Breslow’s depth is over 4mm?
50%
what’s the 5 year survival rate if the Breslow’s depth is less than 1mm?
95-100%
what does ‘in-situ’ mean?
when abnormal cells are present but have not spread to nearby tissue
what does localised mean?
cancer is limited to the place where it started with no sign of spread
what does regional mean?
cancer has spread to nearby lymph nodes, tissues or organs
what does distant mean?
cancer has spread to distant parts of the body
