Dermatology Flashcards
(237 cards)
what is a plaque?
a raised flat-topped lesion, usually more than 2cm in diameter
what is pityriasis alba?
hypopigmentation of skin, commonly seen on children’s faces, especially asian
often resolves spontaneously
appearance of basal cell carcinoma?
pearly (translucent, shiny) papule, often skin coloured, and central ulcer/depression, rolled telangiectatic edge, usually on face in sun exposed site
telangiectatic vessels of surface account for common symptom of contact bleeding
metastases rare
can spread along bony passages into the skull
slowly causes local destruction if left untreated
excision is best
skin signs of coeliac disease?
dermatitis herpetiformis-very itchy/burning blisters on elbows, scalp, shoulders, ankles.
causes of pyoderma gangrenosum?
IBD myeloma neoplasia AI hepatitis wegener's granulomatosis
signs of psoriasis?
symmetrical, well-defined red plaques with silvery scale on extensor aspects of elbows, knees, scalp and sacrum.
flexures e.g. axillae, groin and umbilicus also frequently affected, but lesions non-scaly.
why might diet be important to ask about in suspected eczema?
some atopic children have food allergies e.g. dairy products and/or eggs which exacerbate eczema. rarely true intolerance-actual immune response.
role of emollients in eczema and psoriasis?
treat dryness and act as a barrier
greasy emollients are best in severe eczema
require frequent application-8-10 times daily!!
how can absorption of emollients in eczema be increased?
wearing of stockinette suits at night
or paste bandaging?
classification of eczema?
exogenous and endogenous endogenous: atopic discoid hand seborrhoeic venous-erythematous scaly, flaky skin over and above ankle medial malleolus, alongside skin pigmentation, lipodermatosclerosis, varicose veins, venous ulceration and atrophie blanche endogenous eczema of palms and soles, can be episodic acute pompholyx asteatotic exogenous: contact-irritant and allergic photosensitive (?photocontact) lichen simplex/nodular prurigo
aetiology of atopic eczema?
familial disease, strong maternal influence
often +ve FH of atopic disease e.g. asthma, hayfever
TH2 CD4+ T cell activation in skin drives inflammatory process, thought to be secondary to some break in skin barrier function
genetically complex, may be link to filaggrin gene-epidermal barrier protein where may be loss of function mutation
atopic eczema exacerbating factors?
infection (?superantigen effect) and non-infection in infancy (hygiene hypothesis) strong detergents woolen clothes severe stress or anxiety cat and dog fur dairy products and eggs
clinical features of atopic eczema?
itchy erythematous scaly patches, usually symmetrical and often in flexures-in front of elbows, behind the knees, in front on ankles and around the neck
often starts on face in infants before spreading elsewhere
very acute lesions can weep or exude, and can show small vesicles
scratching can produce excoriations (marks from skin picking)
rpted rubbing produces skin thickening (lichenification) with exaggerated skin markings
often reverse pattern of extensor involvement e.g. back of elbows, front of knees, in people with pigmented skin, and can cause hyper-or hypo-pigmentation in these people post-inflammation
skin of upper arms and thighs may feel roughened due to follicular hyperkeratosis
palms may show very prominent skin creases
may be assoc. ichthyosis vulgaris-‘fish like scaling’ of skin which is non-inflammatory and often prominent on lower legs
another name for fungal skin disease?
mycosis
3 groups of pathogenic fungi that commonly affect the outer skin layer?
dermatophytes-cause ‘ringworm’ type of rash
candida albicans
pityrosporum (malassezia genus)-pityriasis versicolor
how do fungal skin infections typically respond to steroid treatment?
hx of rash improving with treatment (due to suppression of inflammation), but worsening and spreading each time it is stopped
pityrosporum is a yeast part of normal skin flora, common in scalp, upper trunk and flexures. in what 3 dermatoses with overgrowth has it been implicated in?
pityriasis versicolor-presents most commonly on trunk in young people with reddish brown scaly macules (flat, circumscribed, non palpable lesion) which are asymptomatic, in darker skin more commonly presents as hypopigmented macular areas
seborrhoeic eczema
pityrosporum folliculitis
complications of atopic eczema?
secondary infection: staph aureus-impetigo, folliculitis
HSV-eczema herpeticum-multiple small vesicles or punched-out crusted papules and erosions assoc. with malaise and pyrexia, needs rapid tment with oral (if apyrexial) or IV aciclovir, give Abx for bacterial secondary infection (can also give BS as routine prophylaxis), complications=herpes hepatitis, encephalitis, DIC and rarely death. need early opthalm r/v if any evidence of ocular involvement-*risk of HSV keratitis and corneal ulcers.
conjunctival irritation
retarded growth
eczema treatment?
educate and explain
avoid irritants/allergens e.g. pet fur
emollients e.g. diprobase cream-can use as soap substitute, zeroderm, zerodouble, aveeno, zerobase, hydromol, eczmol, dermol, regular use may lessen the need for steroid use, creams and ointments to moisturise skin to reduce dryness-ointments best as stay on skin for longer but very greasy so may be used at night and something else during the day
bath oils and soap substitutes e.g. dermol-emollient and can be used as soap substitute and in the bath, as can eczmol and both antibacterial, hydromol can be used as moisturiser and soap substitute, shouldn’t wash just with water
topical therapies: steroids-1% hydrocortisone, eumovate, betnovate, dermovate, immunomodulators e.g. tacrolimus ointment-calicneurin inhibitor-calcineurin required for activation of T cells
adjuncts-oral Abx, antihistamines-sedating before bed e.g. Chlorphenamine or hydroxyzine in children, bandaging e.g. Icthopaste
phototherapy
oral pred, ciclosporin, MTX, azathioprine, mycophenolate mofetil
clinical features of seborrhoeic eczema (also called seborrhoeic dermatitis)?
in young adults presents as erythematous scaling along sides of nose in NL folds, in eyebrows, around eyes and extending into scalp
due to overgrowth of fungus pityrosporum ovale
tment=mild steroid ointment-prescribed for 1-3wks to reduce inflammation of an acute flare, and topical antifungal cream, which is suppressive rather than curative
keratolytics e.g. salicyclic acid can be used to remove scale where necessary
what type of eczema can often be confused with psoriasis?
discoid eczema-well-demarcated scaly patches, espec. on limbs
follows acute/subacute pattern
often an infection component-S.aureus
skin proliferation rate in psoriasis?
skin regeneration takes 4 days in comparison to normal 28 days
so 7 FOLD INCREASE!
psoriasis aetiology?
autoimmune condition, T lymphocyte mediated inflammatory process to particular antigens
Th1 lymphocytes involved, role of ILs and TNF-alpha
genetic component, gene loci involved some same as for RA, crohn’s disease and atopic eczema
clinical features of chronic plaque psoriasis?
pinkish red scaly plaques, with silver scale, on extensor surfaces e.g. knees, back of elbows, also lower back, ears and scalp.
new plaques occur at sites of skin trauma-kobner phenomenon, lesions can become itchy or sore