Dermatology Pathology Flashcards
What are some external causes of skin damage?
Temperature (frostbite, cold urticaria), UV, allergens, irritants, infection, trauma, meds (e.g. photosensitivity with some antibiotics, NSAIDs…)
What is dermatitis artefacta?
Sores caused by patient causing trauma to their own skin.
What are some internal causes of skin damage?
Systemic disease, genetics (e.g. eczema, psoriasis, neurofibromas), drugs (OTC can lead to macule formation), infection, autoimmune disease.
When describing skin lesions, what is considered small?
Less than 5mm.
What word is used to describe a small circumscribed area (i.e. flat rash with no change in texture, only colour)?
Macule
What word is used to describe a larger circumscribed area (i.e. flat rash with no change in texture, only colour)?
Patch
What word is used to describe a small raised area?
Papule
What word is used to describe a larger raised area?
Plaque
What word is used to describe a small fluid filled spot?
Vesicle
What word is used to describe a larger fluid filled spot?
Bulla
What word is used to describe a small pus filled spot?
Pustule
What word is used to describe a larger pus filled spot?
Abscess
What is an erosion?
Superficial loss of epidermis.
What is an ulcer?
Loss of epidermis and dermis (ulcers heal with scarring due to dermal loss).
What is urticaria?
Hives (wheels resulting from mast cell degranulation).
What are purpura?
Red or purple spots on the skin that do not blanch.
What is petechiae?
Small spots on the skin caused by minor bleeds of capillaries.
What is erythema?
Superficial reddening of the skin.
In which systemic conditions may you see skin signs?
Sarcoidosis
Vasculitis - purpuric rash
Malignancy - skin lesion/lymphoma/paraneoplastic phenomena
Autoimmune conditions
Erythema nodosum in pregnancy
What is eruptive xanthoma and when might you see it?
In hyperlipidaemia - loads of fat deposits in the skin.
How can you investigate dermatological diseases?
Bacterial dx suspected:
Charcoal swab
MC&S
If cellulitis have to do blood culture!
Viral dx suspected:
Viral swab for PCR (must go in viral medium)
Swab vesicle/bulla if it erupts
Can do throat swab if systemic illness
Fungal dx suspected: Skin scrapping Nail clipping Hair sample Fungal cultures
Can do punch biopsies of skin if need to do biopsy.
What is leukocystoclastic vasculitis?
Hypersensitivity vasculitis, in which there may be intradermal haemorrhage, seen as petechiae or purpura.
What is acanthosis nigrans and what it is associated with?
Flexular distribtution of hyperkeratosis, hyperpigmentation and papules. Gives velvety appearance.
Associated with insulin resistance, obesity and malignancy.
Name 4 viruses that can cause infection of the skin.
Human papilloma
Herpes simplex
Herpes Zoster
Molluscium contagiosum
Name 4 bacteria that can cause infection of the skin.
Staphylococcus aureus
Streptococcus
Corynebacterium
Ninutissimum
Name 3 yeast/fungi that can cause infection of the skin.
Candida alicans
Pityrosporum
True fungi
Name an ectoparasite that can cause a skin infection.
Scabies
Where can HSV infect?
Can be herpes labialis (primarily affecting the lips), genital or herpes whitlow (affecting fingers/thumb) or even corneal.
How is HSV spread?
Direct person to person contact. Vesicles are full of active virus.
What episode of HSV will be the worst?
1st will be the worst, longest and severe. Likely to be associated with lymphadenopathy and fever.
Why do you get recurrent HSV symptoms after the first episode?
If you leave it alone, symptoms resolve spontaneously (2-3wks), but virus migrates into dorsal root ganglia where it can reactive and travel back down the peripheral nerves (usually the ones it come up in the first place, hence why infection tends to be in same place).
I.e. it is latent.
What can trigger an episode of symptoms from the HSV?
Variety of triggers, e.g. immunosuppression with cold or stress etc.
What symptoms are associated with HSV?
Vesicles and pustules grouped closely together. Where skin is thin, will see multiple ulcers/erosions. All look roughly the same (monomorphic).
What 3 groups of people is it essential that avoid getting HSV?
Pregnant - has very damaging effects on unborn child (only if not already got it before pregnancy).
Immunosuppressed, as can go from trivial infections to life threatening.
Atopic eczema - can lead to widespread infection.
What group of people are more likely to get coldsores on their hands (whitlow Herpes)?
Healthcare workers.
How can you treat HSV infection?
Aciclovir (topic if small area, or oral if more diffuse).
Is resistance an issue with HSV infection?
Not unless very severe.
What condition does infection with herpes zoster virus cause?
Chickenpox or shingles.
If you meet the virus for the first time you get chickenpox, but virus doesn’t go (resides in vestibular ganglion after symptom resolution) and it shouldn’t reactive but if it does - causes shingles (CANNOT have shingles if never had chickenpox).
What is chickenpox?
Widespread vesiculopustural episode and systemically unwell.
Once crusted and liquid dried up, no longer infectious.
What is shingles?
Lots of little vesicles grouped together in dermatomal distributions, can cross midline but not much. Preceded (4 days earlier) by pain and constitutional symptoms.
Can get post-herpetic neuralgia afterward - horrible burning pain after blistering gone.
In which group of people is it essential to avoid exposing to HZV?
Pregnant - very easily crosses placenta.
IF HZV in ophthalmicological region - what must you do?
Refer to ophthalmologist to test eye function.
What can HZV cause that HSV can’t?
Scaring.
How do you treat HZV infection?
Aciclovir, treat quickly.
What is scabies?
Infection cause by an ectoparasite. One of the itchiest things you can get.
How is scabies spread?
Human to human contact. Bugs usually on their hands and if you have close contact with someone for at least a minute can spread.
What are the symptoms of scabies? How does it manifest and how do you know it is scabies?
Might not know they have it for 5-6wks, after 6wks may see papules and vesicles in webbed parts of hands, after this become allergic to mite faeces –> allergic reaction, which is very very itchy (esp. at night). Must look for obvious burrows. Once you see the burrows you know it is scabies.
How do you treat scabies?
Treat patients and their contacts (even if asymptomatic). Permathin cream (liclear, which is made from a neurotoxin that fries the mite brains). Must put it everywhere apart from hair on head, leave for 12-18 hours and wash it off, then repeat 7 days later).
NB - itch can last for a few weeks after, can use topical steroids to reduce itch.
What are warts?
Outgrowths of skin caused by a type of human papilloma virus.
What is the peak incidence for warts?
12-16 years.
What are the different types of warts?
Common - usually symptomless, most regress within 2y.
Plantar - mostly in children and regress within 6mnths.
Genital - usually sexually transmitted
Others incl plane/filliform/mosaic
How are warts treated?
May be left as they are harmless.
Chemical paints, cryptotherapy (with liquid nitrogen), imiquimod (genital) and others.
What is the orf virus?
Mainly causes sores around mouths of sheep but can infect humans (mostly hands?). No treatment and can trigger erythema multiforme.
What does infection with molluscum contagiosum cause?
Pearly, elevated pink lesions.
What age does incidence of infection with molluscum contagiosum peak?
10y.
What is the treatment for infection with molluscum contagiosum?
None, cryptotherapy, expression and antiseptic.
What is impetigo? What is it caused by? What is its appearance?
Golden dry, flaky chunks, highly contagious. Can spread really easily through contact.
Usually staph/strep/both infection. Most commonly - staph aureus. Can get it anywhere, most commonly HN region.
How do you treat impetigo?
Rx - antibx to treat both (localised = topical, diffuse = oral).
What is a furuncle?
Abscess/infection in the hair follicle. Most commonly caused by by staph aureus.
How can you treat a furuncle?
Drain pus and give antibiotics.
Dip stick urine to check for diabetes if recurrent, as diabetics at higher risk of developing these.
What is ecthyma?
Crust and rim of erythema. Skin infection characterised by crust under which there are ulcers. Most commonly caused by staph aureus.
How do you treat ecthyma?
Oral antibiotics.
What is erysipelas? What symptoms are associated with erysipelas?
Streptococcus infection of skin. More superficial than cellulitis. Skin forms raised plateau of erythema and is very hot to touch. Systemically unwell and quite high mortality. May also have fever and rigours.
How do you treat erysipelas?
IV antibiotics. Cannot wait for oral stuff to kick in.
What is cellulitis? What symptoms are associated with it?
Swollen, red and hot. Patient will be sick (fever, rigours) if extensive cellulitis. Caused by a streptococcus infection in deeper layers of skin.
Where is cellulitis most common?
Lower limb, below the knee.
If very severe cellulitis what may occur?
Skin breaks down and ulcerates.
How might cellulitis happen?
Cracks in skin (e.g. from athletes foot), ulcers - any portal of entry allows for streptococcus to enter deeper layers of skin and spread.
How do you treat cellulitis?
Hospitalised, IV antibiotics for staph and strep.
What is the most common yeast infection?
Candida albicans.
Where is it common for obese people to get candida albican infections?
If they don’t wash properly, can get under breasts, as it likes sweaty, moist areas.
What is the appearance of a candida albican infection?
Brick red erythema and satellite pustules (filled with yellow pus).
Who else may be at risk of a candida albican infection?
Hairdressers, bar staff etc. who have their hands wet.
What is paronchyia?
Inflammation of the nail fold, can be acute or chronic.
What is the commonest cause of chronic paronchyia?
Candida albicans, which has penetrated into nail fold, will see yellow pus discharge.
What is the commonest cause of acute paronchyia?
Staph aureus.
How do you treat canidida albicans infection?
Clotrimazole for local treatment (canisten) or if difficult place, may need anti-candidial drugs.
What is tinea pedis?
Athlete’s foot - lots of white, lacerated skin and flakey bits of skin. Really common.
What causes tinea pedis/corpis/cruris/barbre etc.?
Dermatophytes (fungal infection of the skin).
How do you treat tinea pedis?
Clotrimazole or tolnaftate
What is tinea corpis? How do you investigate it?
Fungal infection of the body. Aka. ring worm. Will see enlarging rings and flakey bits at the edge. Dermapack to microbiology if unsure of diagnosis (scrapping from ends as healthiest fungus there).
What is tinea cruris?
Fungal infection of the crotch area.
What is tinea cognito?
Fungal infection of the skin masked by topic corticosteroid use. Do not use steroids on fungal infections as it will spread.
What is tinea barbre and how is treated directly from other tineas?
Fungal infection of hair follicles. Deeper and won’t respond to topical treatment alone, must use oral and topical treatment.
What is kerion?
Fungal infection of scalp. More common in children 9as they produce less sebum). Leads to very swollen, sore scalp.
Can send hair to microbiology.
How is kerion treated?
Drainage and antibiotics (oral and topical).
What is a carbuncle?
Collection of boils that develop under the skin.
What infections of the skin are related to staph aureus?
Boils, carbuncles, styes, folliculitis, impetigo, ecthyma, ezcema flare ups.
What infections of the skin are related to streptococci?
Impetigo, ecthyma, erysipelas, cellulitis, eczema flare-ups (necrotising fascitis, guttate psoriasis).
What infections of the skin are related to corynebacterium. miniutissimum?
Erythrassma, pitted keratolyis.
What infections of the skin are related to Candida?
Thrush (oral, vaginal), balantitis, angular stomatitis, intertrigo, nappy rash, chronic paronychia.
What infections of the skin are related to true fungi?
Tinea pedis/cruris/corpis/faceii/barbae, onychomycosis.
What would result if the skin failed to be a barrier to infection?
Sepsis
What would result if the skin failed to regulate temperature?
Hypo and hyperthermia
What would result if the skin failed to play its role in vitamin D synthesis?
Renal failure
What is erythroderma?
A descriptive term - any inflammatory skin disease affecting <90% of the total skin surface.
What can cause erythroderma?
Psoriasis, eczema, drugs, cutaneous lymphoma, hereditary disorders.
How do you treat erythroderma?
ITU/burns unit. Remove offending drugs, fluids and nutrition (avoid albumin excess), temperature regulation, emollient to protect skin (liquid paraffin and soft white paraffin mix (protection and moisturise), oral and eye care (e.g. eye drops), anticipate and treat infection. Treat symptoms (e.g. itch) and underlying cause.
Give an example of a mild drug reaction.
Morbilliform exanthema (macularpapular rash).
Given examples of severe drug reactions.
Erythroderma, Steven Johnson Syndrome/Toxic epidermal necrolysis, DRESS
What is SJS/TEN?
Two conditions thought to be part of same spectrum. SJS less severe (less skin involvement).
Secondary to drugs (e.g. antibiotics, anticonvulsants, allopurinol, NSAIDs).
What are the clinical features of SJS?
Fever, malaise, arthralgia, rash (maculopapular target lesions, blisters, erosions covering <10% skin surface), mouth ulceration (greyish white membrane, haemorrhagic crusting) ulceration of other mucous membranes (eyes, genitalia).
What are the clinical features of TEN?
Prodromal febrile illness, ulceration of mucus membranes, rash (macular, purpuric or blistering and becomes confluent). Sloughing off of large areas of dermis. High mortality.
Nikolsy’s sign - rub the skin, and it leads to exfoliation of the outer layer.
What are the long term complications of TEN/SJS?
Pigmentary skin changes, scarring, eye disease and blindness, nail and hair loss, joint contractures.
How do you treat TEN/SJS?
Stop culprit drug. Supportive - high dose steroids, IV Ig, anti-TNFalpha, cyclosporin.
What can be used to assess mortality in TEN/SJS?
SCORTEN (graded 1-5 and considers age, malignancy, HR, initial epidermal detachment, serum urea, serum glucose, serum bicarbonate).
What is DRESS?
Drug reaction with eosinophilia and systemic symptoms.
Adverse drug reaction occurring 2-8wks after drug exposure.
What are the signs of DRESS?
Eosinophilia with derranged LFTs, lymphadenopathy and other organ involvement.
What are the symptoms of dress?
Fever, widespread rash.
How do you treat DRESS?
Stop causative drug, symptomatic and supportive, systemic steroids +/- immunosuppression or immunoglobulins.
What is erythema multiforme?
Hypersensitivity reaction usually triggered by infection (most commonly HSV and then mycoplasma pneumonia).
What are the symptoms of erythema multiforme?
Abrupt onset of up to 100s of lesions over 24h (distal to proximal), palms and soles, mucosal surfaces (=EM major - more serious), evolves over 72h (pink macule become elevated and may blister in centre –> target lesions).
How do you treat erythema multiforme?
Self-limiting, resolves over 2wks (can take up to 6wks).
What is pemphigus?
Skin disorders that cause blistering of the skin, commonly affecting the mucous membranes of the mouth.
What causes pemphigus?
Autoimmune disease where antibodies are targeted at desmosomes.
What are the signs/symptoms of pemphigus?
Nikolskys sign may be positive. Easily rupturing flaccid blisters on skin (may appear as ulcer/erosion). Common sites - face, axillae, groins (may also affect mouth, nose, eyes, genitalia).
What is pemphigoid?
Autoimmune disease where antibodies are direct at the demo-epidermal junction. So intact dermis forms the roof of the blister - these blisters are therefore normally intact.
How could you image these blisters in pemphigoid and pemphigus?
Immunofluorescence and histopathology.
What are the main differences between pemphigoid and pemphigus?
Pemphigoid more common and seen in elderly patients, blisters in tact and tense, patients well even fi extensive.
Pemphigus - uncommon, middle aged, blisters very fragile, mucous membranes usually affected, patients unwell if extensive.
How do you treat pemphigoid?
Topical steroids (systemic if diffuse).
How do you treat pemphigus?
Systemic steroids, dress erosions, supportive.
What is eczema herpeticum?
Disseminated herpes virus infection on background of poorly controlled eczema.
What is the appearance and symptoms of eczema herpeticum?
Monomorphic blisters and pouched out erosions, generally not itchy. Fever, lathery, lymphadenopathy.
How do you treat eczema herpeticum?
Aciclovir, mild topical steroid to treat eczema. If periocular –> refer to ophthalmologist.
If adults consider underlying immunocompromise.
What is a staphylococcal scalded skin syndrome? What are the symptoms?
Staph infection that leads to diffuse erythematous skin rash with tenderness (flexural). Blistering and desquamousation follows (staphylococcus produces toxins that target Desmoglein 1). Fever and irritability also common.
Who are SSSS seen in?
Children, immunocomp adults.
How do you treat SSSS?
Admission, IV antibiotics, supportive care.
Generally resolves within 5-7 days.
What is urticaria?
Central swelling surrounded by erythema and dermal oedema. Itches, burns (histamine release into dermis). Tends to have fleeting nature (<14h).
What is angiooedema?
Deeper swelling of skin or mucous membranes.
What are the two types of urticaria?
Acute <6wks
Chronic >6wks
What are the causes of acute urticaria?
Idiopathic, infection (viral), drugs/food (IgE mediated).
How do you treat acute urticaria?
Oral antihistamines, oral steroids. Avoid opiates and NSAIDs as they exacerbate.
What can cause chronic urticaria?
Idiopathic/autoimmune, physical (press, cold, light trauma), vasculitic (inflammation of blood vessels in skin, more associated with burning sensation).
How is chronic urticaria managed?
Chronic spontaneous urticaria can use omalizumab. Little role for oral steroids.
What is psoriasis?
Chronic immune mediated disease where patients develop sharply demarcated erythematous plaque with micaceous scale
In which age groups is psoriasis most common?
20-30y, 50-60y
What is the aetiology of psoriasis?
Polygenic predisposition (FH, HLA-Cw6, psoriasis susceptibility regions (PSORS1-9)
Environmental triggers (infection, drugs, trauma, sunlight)
What is acne vulgaris?
A disease of the pilo-sebaceous unit
Where does acne vulgaris affect most on the body?
Face
Chest
Back
What is the medical term that describes a blocked follicle?
Comedo(nes)
What is the pathogenesis of acne vulgaris?
Androgen stimulate sebaceous follicles to over produce sebum so follicles become blocked
Hyperkeratinization of epithelium –> accumulation and follicle blocking
Propionibacterium acnes replicates within follicle –> releases lipase –> sebum converted to FFA –> release of cytokines and infalmmation
What is a closed comedo?
White head
What is an open comedo?
Blackhead
When is the peak onset of acne vulgaris?
15-18y
What is the dose of isotretonin use to treat acne vulgaris?
1mg/kg/day for 16 weeks
Who can prescribe isotretinoin?
Skin specialists only
What is isotretinoin?
A retinoid
What is the most effective treatment for stubborn/severe acne?
Isotretinoin
What are the drawbacks with isotretinoin?
Very teratogenic Many SEs (dry skin, hair loss, mood swings/depression/suicide, abnormal LFTs, hypertriglyceridaemia)
What are the different types of acne vulgaris?
Mild - occasional comodones, papules and pustules
Moderate - multiple pustules, nodules on trunk
Severe - cystic, large nodules, persistent trunk involvement, scarring
What medications can cause acne vulgaris?
Lithium
Glucocorticoids
Anabolic steroids
What conditions can cause acne?
PCOS
Hormonal imbalance
Infection
Stress
What topical treatments can be used for acne vulgaris?
Retinoids
Benzoyl peroxide
Antibiotics (clindamycin, tetracycline, erythromycin)
What systemic treatments can be used for acne vulgaris?
Antibiotics: tetracyclines, erythromycin
Anti-androgens, e.g. COCP/dianette
Isotretinoin
Light based treatments
What is eczema?
A common INFLAMMATORY skin condition
Where does eczema tend to affect?
FLEXURAL surfaces
What age group is most affected by eczema?
Babies/children
60% clears by adulthood
Define atopic eczema
An itchy skin condition in the last 12 months, + 3 of:
- Onset before 2y
- Hx flexural involvement
- Hx of generally dry skin
- Hx of another atopic dx (asthma/hayfever) or hx in first degree relative if <4y
What is the pathogenesis of eczema?
Epidermal barrier dysfunction due to genetic + environmental factors
What is the key role implicated in eczema?
Filaggrin gene
What atopic diseases are associated with eczema?
Atopic eczema, asthma, hayfever, food allergy
What is the atopic triad?
Asthma
Hayfever
Eczema
What are the histological findings in eczema?
Spongiosis (intracellular oedema) within the dermis
Acanthosis
Inflammation (superficial perivascular lymphohistiocytic infiltrate)
What is acanthosis?
Thickening of the epidermis
What are causes for acute flares of eczema?
Viral illness
Period of poor health
Environmental triggers (cold, heat, allergens, e.g. HDM, cat/dog dander)
Food allergies
What are the clinical features of eczema?
Itch, redness, scaling, papules, vesicles
What chronic changes can you get in eczema?
Lichenification
Plaques
Fissuring
What is lichenification?
Thick, leathery patches of skin
What are the main two classes of eczema?
Exogenous - external
Endogenous - internal
What are the ‘external’ eczemas?
Contact dermatitis - irritant, allergic
Lichen simplex
Photoallergic/photoaggrevated
What are the ‘internal’ eczemas?
Atopic Discoid Venous Seborrhoeic dermatitis Pomphloyx Juvenile plantar dermatitis
What type of hypersensitivity reaction is allergic contact dermatitis?
Type 4 (delayed) Can take 48-27h to develop reaction
What is the pathophysiology of allergic contact dermatitis?
APC take allergen to LNs and present o naïve T cells
Clonal expansion of these T cells + T cells released into bloodstream
When T cells next encounter hapten –> mast cell degranulation, vasodilation + neutrophils are recruited
What is irritant contact dermatitis?
Skin is injured by friction (e.g. microtrauma, cumulative) and environmental factors (cold, over exposure to water, acids, alkalis, detergents + solvents)
What occupations are at risk of irritant contact dermatitis?
Hairdressers
NHS staff
Cleaners
What is nappy rash?
Irritant contact dermatitis possibly from wipes
How is patch testing done?
Potential allergens applied, removed after 3 days, re-assess after another 3 days
Who do you see seborrheic dermatitis in?
Infants (<6m usually)
Where does seborrheic dermatitis tend to affcet?
Areas rich in sebaceous glands - scalp, face, upper trunk
What causes seborrheic eczema?
Malassezia yeast
What do the lesions look like in seborrheic eczema?
Red, sharply marginated lesions covered with greasy looking scales
What is a common precursor to adult seborrheic eczema?
Dandruff
How is seborrheic eczema treated?
Ketoconazole
If an adult has very severe seborrheic eczema what must you consider?
HIV testing
What does discoid eczema look like?
Circular plaques of eczema
Where does discoid eczema develop?
Can develop at sites of trauma/irritation
What is pompholyx/vesicular eczema?
Affects palms + soles
V. itchy
Sudden onset crops of vesicles
Desquamation
What is asteatotic eczema?
Very dry, cracked, scaly skin
Tends to be on shins
What can cause asteatotic eczema?
Hot climate
Excessive washing/soaps
Where does venous eczema tend to be?
On ankle and lower leg
What causes venous eczema?
Increased venous pressure –> oedema
What can help with venous eczema?
Resolution of oedema - e.g. compression stockings
What is eczema herpeticum?
Disseminated HSV infection
What does eczema herpeticum present like?
Fever
Unwell
Itchy clusters of blisters + erosions
Swollen LNs
What strains of HSV can cause eczema herpeticum?
HSV 1 and 2
How do you manage eczema herpeticum?
Admission
Antivirals
Consider secondary bacterial infection
How do you treat eczema?
Pt education Avoid causative/exacerbating factors Emollients (moisturisers) Soap substitutes Intermittent topical steroids Antihistamines/antimicrobials Calcineurin inhibitors
What types of emollients are there?
Ointments - greasy, but effective
Creams
Lotions - most watery
Give two examples of calcineurin inhibitors
Topical Pimecrolimus and Tacrolimus`
What other treatments may be used for severe eczema?
UV light
Immunosupression - e.g. azathioprine, ciclosporin, mycophenolate mofetil, methotrexate
What two regulatory bodies can approve medicines for use in the uk?
MHRA - medicines and healthcare products regulatory agency
EMA - European medicines agency
What are the three types of medicines used without a license?
Unlicensed
Off label
Specials
What does unlicensed mean?
Not approved for use in the Uk
What does off label mean?
A licensed medication that is being used for an unlicensed indication
What are common causes of prescription errors?
Lack of knowledge
Mistake writing/generating prescription
Poor communication
No local/national guidelines
Define pharmacology
Branch of medicine concerned with uses, effects and modes of actions of drugs
Define pharmacokinetics
Effect of body on the drug
Define pharmacodynamics
Effect of the drug on the body
What are the four components of pharmacokinetics
Absorption
Distribution
Metabolism
Elimination
In which kinds of diseases may the metabolism of a drug be distributed?
Liver disease
In which kinds of diseases may the elimination of a drug be distributed?
Renal disease
What things must you think about about the pharmacodynamics of a drug?
Individual variation in response
Age of pt, pregnancy risk, DDIs, pharmacogenetics
What are factors that make it more likely patients will adhere to prescribed medication?
Female Married Employed Not paying for prescription Increasing age
What are factors that make it less likely patients will adhere to prescribed medication?
Psychiatric co-morbs Slower acting agents Multiple applications per day Lack of pt education Cosmetic acceptability of treatments Unintentional non-adherence
What is a topical therapy?
Medication applied to the skin
What are the two components of a topical agent?
Vehicle + active drug
What is the vehicle in a topical agent?
Pharmacologically inert, physically + chemically stable substance that carries the active drug
What factors affect the absorption of a topical agent?
Concentrate Vehicle Chemical properties of the drug Thickness/hydration of stratum corneum Temperature Skin site Occlusion
Give examples of vehicles for topical agents
Solution Cream Lotion Gel Tape Paste Shampoo Paint
Give e.g.s of topical drugs
Corticosteroids Antibiotics Antivirals Vitamin analogues Chemotherapy Parasiticidals Coal tar Anti-inflammatories
What are the actions of topical steroids?
Anti-inflammatory + immunosuppressive:
- Regulate pro-inflammatory cytokines
- Supress fibroblast, endothelial + leukocyte function
- Vasoconstriction
- Inhibit vascular permeability
How many g does a finger tip unit equate to?
0.5g
What area of skin should a finger tip unit treat?
Double the size of one hand
What are side effects of topical steroids?
Thinning/atrophy Striae Bruising Hirsutism Telangiectasia Acne/rosacea/perioral dermatitis Glaucoma Systemic absorption Cataracts
What systemic treatments may be used in dermatology?
Retinoids
Traditional immunosupressants
Biolgoics
What vitamin are retinoids analogues of?
Vitamin A
What are the actions of retinoids?
Normalise keratinocyte function
Anti-inflammatory and anti-cancer effects
What is a serious complication of retinoid use?
Teratogenicity
What are side effects of retinoids?
Chelitis (dry lips), xerosis (dry skin)
Increased serum transaminases and triglycerides
Rarely psychiatric, eye, bone side effects
What immunosupressants may be used to treat dermatological diseases?
Oral steroids Azathioprine Ciclosporin Methotrexate Mycophenolate mofetil
What are the adverse effects of immunosupressants?
Risk of malignancy + infection
What blood tests are needed for patients on methotrexate?
LFTs, FBC
What blood tests are required for those on ciclosporin?
Renal function tests
What blood tests are required for those on azathioprine?
FBC
What are biologics?
Genetically engineered proteins derived from human genes that inhibit specific components of the immune system
What does the suffix ‘-cept’ indicate?
A biologic that is genetically engineered fusion protein
What does the suffix ‘-mab’ indicate?
Biologic that is a monoclonal antibody
With relation to biologics - what does the infix ‘zu’ indicate?
Humanised
With relation to biologics - what does the infix ‘ix’ indicate?
Chimeric
With relation to biologics - what does the infix ‘u’ indicate?
Fully human
With relation to biologics - what does the infix ‘li/l’ indicate?
Immunomodulator
What are the adverse effects of biologics?
Risk of infection - may reactive TB, cause serious infection
Risk of malignancy
TNF inhibitors have risk of demyelination
What should people on biologics avoid?
Live vaccines
What resources can you use to get reliable information about a drug?
SPC (summary of product characteristics) SMC BNF BAD guidelines Local formulary
What is Curth’s postulates?
Criteria that can help distinguish between a skin sign and a malignancy occurring together being a chance occurrence or an associated event
What are Curth’s postulates?
Concurrent onset Parallel course Uniform site or type of neoplasm Statistical association Genetic linkage
What are the features of carcinoid syndrome?
Episodic flushing (lasting mins-hours) Facial telangiectasia
What is carcinoid syndrome associated with?
GI carcinoid ONLY if there are liver mets
Bronchial or ovarian cancers (can occur without liver mets)
What are the features of paraneoplastic pemphigus?
Erosive stomatitis, rash
What is paraneoplastic pemphigus associated with?
Non-hodgkins, Castlemans disease (produces the autoantibody)
What is erythema gyratum repens?
Concentric erythematous lesions
Assoc. with various malignancies
What is acquired hypertrichosis lanuginosa?
Acute onset of lanugo hairs on face and body
What is acquired hypertrichosis lanuginose associated with?
Colorectal cancer > lung > breast (usually advanced)
What are the features of Leser-Trelat syndrome?
Eruptive seborrheic keratoses
What is Leser-Trelat syndrome associated with?
GI adenocarcinomas
What are the features of Bazex syndrome?
Hyperkeratosis of extremities
Looks like psoriasis
What is Bazex syndrome associated with?
SCC - bronchial, oropharyngeal, GI
Gastric, colon, biliary, adenocarcinomas
What is ectopic ACTH syndrome?
Tumour production of ACTH leads to generalised hyperpigmentation
Why does xs ACTH lead to hyperpigmentation?
ACTH –> inc. MSH –> release of melanin from melanocytes
What is Paget’s disease?
Eczematous plaque at nipple/areola
extends into underlying ductal adenocarcinoma
What skin conditions are strongly associated with cancer in all/most cases?
Carcinoid syndrome Paraneoplastic pemphigus Erythema Gyratum Repens Acquired hypertrichosis Leser Trelat Bazex syndrome Ectopic ACTH Pagets disease
What two conditions are strongly associated with malignancy?
Acanthosis nigricans
Dermatomyositis
What kind of cancer does acanthosis nigrians most commonly precede?
Gastric adenocarcinoma
What are red flags for acanthosis nigricans?
Older patient Rapid onset Other skin signs Involves lips Wt loss
What are the features of dermatomyositis?
Inflammatory myopathy + rash -
- Periorbital heliotrope rash
- Gottron papules
- Shawl sign
- Photosensitive poikiloderma
- Scalp erythema
What are Gottron papules?
Red maculo-papular lesions over knuckles usually
What conditions may be associated with an underlying malignancy?
Bullous pemphgoid Sweets Syndrome Pyoderma gangrenosum Acquired ichthyosis Acquired angioedema Primary systemic amyloid Cryoglobulinaemia
What cancers are associated with Peutz-Jeghers?
Melanosis, colon hamaratomas, colon ca
What cancers are associated with Muir-Torre?
Sebaceous tumours, keratocanathomas, GI, breast, GU
What are the features of neurofibromatosis?
Café au lait spots, axillary freckling, neurofibromas, nerve sheath tumours, carcinoid syndrome, phaeochromocytoma
What are the features of xeroderma pigmentosum?
Inability to repair sun damage
Sarcoma
Leukaemia
GI and lung cancers
What skin signs do you see in IBD?
Erythema nodosum
Pyoderma gangrenosum
What is the pathophysiology of alopecia?
T lymphocyte + cytokine mediated rejection of hair
What are the three types of alopecia?
Totalis - total scalp loss of hair
Universalis - total hair loss of entire body
Areta - patchy loss of hair on scalp
What causes vitiligo?
Destruction of melanocytes via autoimmune process
What is the most common type of non-melanoma skin cancer?
BCCs
What are risk factors for non-melanoma skn cancers?
UV radiation Photochemotherapy Chemical carcinogens Ionising radiation HPV Familial cancer syndromes Immunosupression
Describe the appearance of a BCC
Pearly rolled edge
Telangiectasia
Central ulceration
Arborising vessels on dermoscopy
Give e.g.s of types of BCC
Pigmented
Morphoeic
How do you treat BCC?
Excision is gold standard
Curettage in some cases
How do you excise a BCC?
Ellipse (with rim of unaffected skin)
What drug can be used for locally advanced BCC that is not suitable for radio or surgery or metastatic BCC?
Vismodegib
How does vismodegib work?
Selectively inhibits abnormal signalling in the Hedgehog pathway
What are SEs of vismodegib?
Hair loss, wt loss, altered taste
Muscle spasms, nausea, fatigue
What cells are SCCs derived from?
Keratinising squamous cells
Where do SCCs tend to occur?
Sun exposed sites
How do SCCs appear?
Tender, scaly/crusted or fleshy growths
Can ulcerate
Of SCC and BCC which are faster growing and more aggressive?
SCC
How is SCC treated?
Excision +/- radio
What SCCs are considered high risk and should be followed up post-treatment?
Immunosupressed pt >20mm diameter >4mm depth Ear, nose, lip, eyelid Perineural invasion Poorly differentiated
What is keratocanthoma?
Variation of SCC
Erupts from hair follicles in sun damaged skin
Rapidly growing
How are keratocanthomas managed?
May resolve itself after a few months
Surgical excision
What are risk factors for melanoma?
UV radiation
Genetic susceptibility - fair skin, red hair, blue eyes, tendency to burn easily
Familial melanoma + melanoma susceptibility genes
What is the ABCDE rule for identifying lesions that may be melanoma?
Asymmetry Border Colour Diameter Evolution
What is the 7 point checklist for identifying melanoma?
MAJOR FEATURES:
Change in size
Change in shape
Change in colour
MINOR FEATURES Diameter >5mm Inflammation Oozing or bleeding Mild itch/altered sensation
What apparatus is used to look up close at lesions on the skin?
Dermoscope
Name the types of melanoma
Superficial spreading malignant melanoma Lentigo maligna melanoma Nodular melanoma Acral lentiginous melanoma Subungal melanoma Ocular melanoma
How do you treat melanoma?
Urgent surgical excision
What is Breslow thickness?
Description of how deep a melanoma has invaded
What kind of excision should be done for a melanoma?
Wide local excision
+ sentinel LN biopsy
What other treatments may be used for melanoma besides surgery?
Chemotherapy
Immunotherapy
What drugs can be used to treat melanoma?
Ipilimumab
Pembrolizumab
Vemurafenib and dabrafenib
How does Ipilimumab work?
Inhibits CTLA-4 molecule
How does Pembrolizumab work?
Targets PD-1 receptor on tumour cell
How does Vemurafenib and dabrafenib work?
Blocks B-RAF protein (only useful in B-RAF mutation)
