Dermatology Flashcards
describe the epidermis
multiple layer of keratinocyte cells
outermost layer; cornified layer of dead cells responsible for the barrier function
innermost layer; basal cells (single layer of keratinocytes)
melanocytes can be found between these layers
what are the functions of skin?
protective barrier sensation (multiple nerve endings) thermoregulation immunological surveillance (Langerhans cells) vitamin D production psychosocial
what should be asked in a dermatology history?
time of onset where/how the skin problem started evolution of change associated symptoms - itch, pain, swelling, bleeding aggravating and relieving factors any treatments tried so far how fair the skin is sun exposure previous skin problems anticoagulants (biopsy) work, school, quality of life
what are you looking for in a skin examination?
location localised/generalised distribution symmetrical size shape colour well/ill-defined other associated locations - scalp, nails, mucosa
describe macules and patches
flat to the surface
macule <5mm
patch >5mm
describe papule and plaques
raised lesion
papule <5mm
plaque >5mm
describe a nodule
raised and round-topped
may be superficial or deep
describe vesicles, bulla and pustules
vesicles; <5mm with clear fluid
bullae/blisters; >5mm with clear fluid
pustule; opaque fluid
describe a cutaneous horn
abnormally thick cornified layer
overlying a pre-malignant lesion causing actinic keratosis or a squamous cell carcinoma
what features of a pigmented lesion indicate malignant melanoma?
asymmetrical irregular border 2 or more colours diameter >6mm evolution
describe acute eczema
high level of inflammation
red oedematous skin
papules and vesicles often present
wet eczema appearance
describe chronic eczema
dry slightly less red changes some thickening of the skin lichenification and fissuring post-inflammatory hypo/hyperpigmentation may also occur
describe the pathophysiology of eczema
genetic predisposition
primary defect; skin barrier dysfunction, water loss, sensitivity
inflammation and pruritus reduce the skin barrier
scratching exacerbates the inflammation
itch-scratch cycle
what are the clinical subtypes of eczema?
intrinsic (eczema); atopic seborrhoeic, discoid, pompholyx, varicose, venous eczema
extrinsic (dermatitis); an extrinsic factor brings about the skin barrier problem, contact irritant and contact allergic dermatitis
describe atopic eczema
most common form particularly in children genetic predisposition chronic relapsing course pattern can vary; face and flexural aspects in children, flexural areas and hands in adults
what are the triggers of atopic eczema?
stress
scratching
secondary infections (staphylococcus, herpes, molluscum)
hot and sweaty conditions
irritants (wool, dust, soap, bubble bath)
allergens (fragrance, preservative in topicals agents or cosmetics, pet dander)
what are the complications of eczema?
due to the defective skin barrier; secondary bacterial infection secondary viral infection contact allergy itch sleep deprivation growth impairment depression social isolation
what is the pharmacological management of eczema?
emollients and soap substitutes; maintenance
anti-inflammatories
topical steroids
calcineurin inhibitors (anti-inflammatory agent) 2nd line after steroids
antibiotics/virals
sedative antihistamines
severe refractory disease; phototherapy
ciclosporin, azathioprine, mycophenolate require side effect counselling
what is the non-pharmacological management of eczema?
dermatology nurse
education in application of cream
wet wraps
clinical psychologist; break the itch-scratch cycle
describe seborrhoeic eczema
classic distribution over the scalp
associated with minimal itch due to an overgrowth of commensal yeast organisms (malassezia)
high prevalence in those with HIV
what is the treatment of seborrhoeic eczema?
mild topical steroids; hydrocortisone
anti-fungals; canesten, daktarin
or a combination of both
describe the presentation and differential diagnosis of discoid eczema
intensely itchy plaques of wet eczema
often on the limbs
often difficult to treat; require potent topical steroids
differential diagnosis; Bowen’s disease (pre-malignant lesions), fungal infection, psoriasis
describe pompholyx eczema
very small blisters on the palmar-plantar surface; hands and feet intensely itchy lateral borders of the fingers within the web spaces can be linked to sweating
describe varicose eczema
bilateral
chronic
may be a Hx of varicose veins, DVT
eczematous change (acute or chronic) develops on a background of lipodermatosclerosis; inverted Champagne bottle leg
haemosiderin; brown, patchy appearance over lower legs
at risk of venous ulceration
what is the treatment of varicose eczema?
lots of emollient
compression stockings
describe asteatotic eczema
very common in hospital and elderly patients
very dry skins
cracks develop in a typical crazy paving pattern
aggravated by soaps and poor nutrition
describe contact allergic dermatitis
extrinsic eczema
delayed hypersensitivity reaction to substances in contact with the skin
causes; nickel, fragrance, hair dye
diagnosis; patch testing
describe contact irritant dermatitis
extrinsic eczema
skin is irritated by noxious agents
common on the hands
treatment; very careful hand care, soap substitutes, frequent emollients
describe psoriasis
benign inflammatory condition FHx significant itch nail changes fluctuating associated potentially destructive arthropathy bimodal peak onset; 20, 50-60yrs
what are the triggers of psoriasis?
stress alcohol physical trauma; burns, repeated rubbing, cuts, abrasions, surgical operation sites (koebner phenomenon) lithium beta blockers ACEi anti-malarials abrupt cessation of oral/topical steroids; substantial flare
describe the pathogenesis of psoriasis
interaction of genetic, immunological and environmental factors
genetic factors; influence subtype and treatment response
predominately driven by T-cells within the epidermis
pro-inflammatory cytokines; TNF, IL-12, 23, 17 cause the hyperproliferation of keratinocytes and angiogenesis
describe chronic plaque psoriasis
most common subtype
symmetrical
well defined
salmon pink plaques
on extensor sites; elbows, knees, sacrum, scalp
thick, silvery scale
auspitz sign; removed/scratched off, pinpoint bleeding
dermal blood vessels become much more close to the skin surface
describe subacute psoriasis
when chronic plaque psoriasis becomes inflamed or fiery red
less obvious scale
what is the treatment of chronic plaque psoriasis?
vitamin D analogues
tar preparations
topical steroids; used in short bursts only
narrow-band UVB; if topicals are ineffective
systemic medications; UVB ineffective
biologics; fail first line systemic agents, sc injection, immunosuppressive
describe erythrodermic psoriasis
deep red appearance
>90% body surface
widespread, exfoliative scaling
extremely unwell; fever, malaise, raised WCC
what are the complications and treatment of erythrodermic psoriasis?
defective thermoregulation
fluid and protein loss
high output HF
secondary cutaneous infection
supportive care; fluids, emollients, skin care
systemic treatment
describe pustular psoriasis
extensive sheets of small pustules skin red and painful well-demarcated patches and plaques mortality of up to 10% significant systemic symptoms; fever, malaise
what is the treatment of pustular psoriasis?
supportive; fluids, emollients, skin care
systemic therapy required to control the skin
describe palmoplantar psoriasis
exclusively affects the palms and soles pustules on a background of erythema; instep of soles, heels of palms symmetrical painful itchy significant functional impairment
what is the treatment of palmoplantar psoriasis?
tar
potent topical steroids
hand and foot PUVA
systemic agents
describe guttate psoriasis
common in teenagers
classically follows a streptococcal throat infection
small teardrop plaques
particularly over the trunk
may clear in 4-6 weeks or cause chronic psoriasis
what is the treatment of guttate psoriasis?
vitamin D
topical steroid preparation
tar preparations
phototherapy; UVB, responds extremely well
describe flexural psoriasis
reflects the flexures; axilla, sub-mammy areas, groins
very well demarcated red, glistening plaques
minimal scale
due to occlusion of the areas
associated with secondary candidiasis infection; seen as satellite lesions, papule and pustules situated away from the plaques
what is the treatment of flexural psoriasis?
mild topical steroid and anti fungal mix
topical calcineurin inhibitor; causes local irritation in the first few days
what is the treatment of psoriasis?
topical; vitamin D analogues phototherapy; narrow-band UVB, PUVA widespread; oral psoralen local; topical psoralen limit of total lifetime exposures of PUVA, significant risk factors for skin cancer
what are the systemic agents that are used to treat psoriasis?
methotrexate; inhibits dihydrofolate reductase, used in skin and joint disease, immunosuppressive (monitor blood count and LFTs)
ciclosporin; only skin disease, immunosuppressive, renal complications and hypertension
acitretin; vitamin A analogue, non-immunosuppressive
biologics; anti-TNF, IL12/23, IL17, those who have failed standard systemic treatment options
apremilast; oral inhibitor of phosphodiesterase four, non-immunosuppressive
what are the complications of psoriasis?
psoriatic arthropathy; can be destructive, lead to enthesitis, requires early intervention with systemic agents
metabolic syndrome; increased risk of CVD (could be improved by methotrexate)
psychological/psychiatric impairment; depressed, anxious, unemployed, socially isolated
describe psoriatic nail dystrophy
pitting; coarse, >5
oil-drop spots
oncholysis; may be caused by subungal hyperkeratosis
more prone to secondary fungal nail infection
describe psoriatic arthropathy
often asymmetrical can affect small or large joints, sacroiliac and spinal joints enthesitis sausage deformity of the fingers arthritis mutilans
describe psoriatic scalp disease and its treatment
can be very extensive can cause significant distress itch excessive scaling falling onto clothing
treatment; shampoos, pomades, steroid shampoos or gels, olive oils, coconut oils, systemic therapy
describe acne vulgaris
chronic inflammation of the pilosebaceous unit
onset usually in adolescence
describe the pathophysiology of acne
increased sebum production
blockage/plugging of the pilosebaceous unit; obstruction of the outflow of sebum
abnormal microbial colonisation of the unit; propionibacterium acnes
inflammation
what are the clinical signs of acne?
open comedones; blackheads closed comedones; whiteheads papules and pustules; blocked follicle ruptures into the skin nodules cysts scarring
what is the difference between open and closed comedones?
open; blockage of the follicular opening, still open to the surrounding skin
closed; follicle remains closed over the swollen sebaceous gland
describe papules and pustules in acne
increased inflammation
development of pus
often following the rupture of a wall of a closed comedone
describe nodules and cysts in acne
larger and deeper within the skin
significant inflammatory component
can be very painful
at the most risk of leaving severe scarring
describe scarring in acne
usually improve 6-12 months after the inflammatory phase has been resolved
ice pick scarring
hypertrophic scarring
exacerbated by excessive picking or squeezing
what are the aggravating factors for acne?
PCOS
CAH; endocrine causes of hyperandrogenism
drugs; steroids, hormones, anti-convulsants
pregnancy
occlusive oil-based cosmetics
smoking
define mild acne
classically involves comedones and a few small pustules
define moderate acne
papulopustular lesions in a wider area or failure of mild acne to respond to therapy
define severe acne
widespread nodular cystic lesions, or a failure of moderate acne to response to treatment, or a patient with significant psychological upset associated with their acne
what is the treatment of mild acne?
topical agents; benzoyl peroxidase
topical retinoid; derived from vitamin A, particularly effective for comedonal
cream formulation; least irritant
second line topicals; combine benzoyl peroxidase with an antibiotic or a retinoid
topical antibiotics; never used as a mono therapy
topical treatment; synergistic with oral therapy
what is the treatment of moderate acne?
systemic antibiotics; tetracyclines, 6-12 weeks, tetralysal and doxycycline
OCP
topical agents; synergistic with systemic treatments
what is the treatment of severe acne
isotretinoin; roaccutane vitamin A derivative/retinoid 4-6 month course 40%; excellent response 40%; minimal recurrence 20%; may require a second course
what is the mechanism of action of isotretinoin?
dramatic reduction in sebum production
inhibition of P. acnes
anti-inflammatory
what are the side effects of isotretinoin?
dry skin and mucosae nose bleeds flare of eczema muscle aches hepatitis elevated triglycerides photosensitivity teratogenicity depression
describe rosacea
chronic inflammatory skin disorder crops of papules and pustules background of erythema and telangiectasia affects convexities increased age group females fairer skin type
what are the causes of rosacea?
multifactorial; UV exposure demodex mite and skin peptide activation genetic factors vascular abnormalities
what are the clinical features of pustular rosacea?
papules and pustules on the convexities; nose, cheeks, chin, forehead
no comedones
rhinophyma
lymphedema of the skin of the nose
ocular involvement; up to 50%, most commonly blepharitis
what are the clinical features of erythematous rosacea?
frequent facial flushing
over months-years, may become persistent
triggers; alcohol, spicy food, UV, caffeine, topical steroids
extremely sensitive skin to any topical applications or cosmetics
may have ocular involvement
what is the treatment of pustular rosacea?
UV protection
topical ivermectin 1st line
topical metronidazole
orał tetracyclines; 4-6 month course, failing or adjunct to topical agents
eye involvement; lid hygiene, refer to ophthalmology
what is the treatment of erythematous rosacea?
UV protection
emollients; settle the highly sensitive skin
trigger avoidance
laser therapy
cosmetic camouflage
topical brimonidine gel/mirvaso; severe flushing, alpha-2 agonist, vasoconstriction temporarily, some pallor
eye involvement; lid hygiene, refer to ophthalmology
describe impetigo
a common superficial bacterial skin infection
pustules
heavy-coloured crusted erosions
usually caused by staph aureus
non-bulbous; caused by group A beta-haemolytic strep
acutely contagious; avoid using the same face cloth and towels
what is the treatment of impetigo?
relatively localised
simple antiseptics; chlorhexidine to wash
topical antibiotics; fucidic acid or fucidin
more widespread, resistant to topical treatment, patient is unwell; swab, initiate antibiotics (flucloxacillin or erythromycin)
what are the clinical features of venous stasis?
afebrile itch Hx of DVT or varicose veins bilateral light pink/red crusting, weeping not tender varicose veins skin pigmentation and fibrosis inverted Champagne bottle leg normal inflammatory markers
what are the clinical features of cellulitis?
febrile pain usually unilateral intense erythema tender no crusting occasionally blisters lymphadenopathy/lymphadenitis necrosis if severe athletes foot/ulceration; blood sugar, HbA1c raised inflammatory markers
define cellulitis
acute, subacute or chronic area of inflammation and infection of subcutaneous tissue
describe erysipelas
similar to cellulitis sometimes in the face acute well defined more superficial; affecting the dermis and upper subcutaneous tissue
what is the treatment of cellulitis and erysipelas?
antibiotics
analgesia
blood cultures; if they are systemically unwell with a pyrexia
swab in areas of skin that may be broken
describe necrotising fasciitis
medical and surgical emergency
cellulitic-looking process
pain out of keeping with what you initially see
can become systemically unwell; septic shock
what are the causes and treatment of necrotising fasciitis?
typically polymicrobial
group A haemolytic strep
clostridium perfringens
if progresses; will most likely require surgical debridement, high mortality rate
initiate IV antibiotics, swab any areas that are broken
describe chicken pox
caused by varicella zoster acute fever prodrome; feeling unwell subsequent vesicular eruption incubation period; 10-21 days vesicles can take 3 weeks to clear and can leave residual scars
what is the management of chicken pox?
usually symptomatic mild analgesia rest at home fluids calamine lotion; relief, topical immunocompromised; antivirals, acyclovir, varicella zoster globulin
describe shingles
herpes zoster
localised, vesicular, painful rash
reactivation of the varicella zoster virus
typically unilateral
dermatomal distribution; will not cross the midline
what is the treatment of shingles
antivirals; acyclovir
simple analgesia
secondary infection; treat with antibiotics
what happens if shingles affects the facial nerve?
Ramsay-Hunt syndrome
can cause a degree of facial paralysis and hearing loss in the affected ear
describe the pain that occurs after the resolution of the shingles rash
post-herpetic neuralgia
treatment; amitriptyline, can have a significant impact on patient
describe cold sores
herpes simplex virus
localised vesicular eruption
often triggered by a preceding illness, generally being run down, UV light
what are the causes of cold sores?
HSV1; oral and facial cold sores
HSV2; genital and rectal infections, anogenital herpes
what are the complications of herpes simplex virus?
eye involvement; dendritic ulcers
disseminated eczema herpeticum; if the patient has pre-existing eczema
erythema multiforme; classic targeted lesions
what is the treatment of cord sores?
acyclovir oral
prophylactic dose if recurrent
viral swab of any vesicular eruption; exclude underlying HSV
describe the different types of tinea fungal infections
tinea pedis; foot tinea corporis; body tinea capitus; scalp tinea cruris; groin tinea unguium; nails tinea incognita; masked by steroids tinea manuum; hand
what are the investigations and treatment of cutaneous fungal infections?
swab for fungal O&S
skin scrapings
woods light
nail clippings; tinea unguium
stop topical steroid
topical (lamisul) or oral terbinafine, itraconazole or fluconazole
duration depends on site
monitor LFTs if long course
describe pityriasis versicolor and its treatment
scaly hypo or hyper pigmented patches on the chest and back
common yeast infection
associated with humid environments, travelling
should respond to a 5 day course of ketoconazole shampoo
persistent; oral antifungals, itraconazole, fluconazole