Dermatology Flashcards
What is acne vulgaris?
Affects face, neck & upper trunk
There’s obstruction of the pilosebaceous follicle with keratin plugs, which results in comedones, inflammation & pustules.
Who gets acne vulgaris?
80-90% of teenagers, 60% seek medical advice
What bacteria is present in acne vulgaris?
Propionibacterium acnes
Pathology of acne vulgaris
Ance is a disorder of the pilosebaceous unit (hair follicle + sebaceous gland)
There’s increased sebum production (due to androgenic hormones), bacterial colonisation (P. acnes) and inflammatory mediators
Development of acne is multifactorial
Risk factors for acne vulgaris
Puberty PCOS Congenital adrenal hyperplasia Exogenous steroids/testosterone Medications - steroids, anti epileptics, EGFR inhibitors High glycemic index foods
Symptoms of acne vulgaris
Comedones - dilated sebaceous follicle. If the top is closed = whitehead, if the top is open = blackhead
Inflammatory lesions when the follicle bursts = papules and pustules
an excessive inflammatory response = nodules and cysts
Scarring - ice pick scars and hypertrophic scars
Drug induced acne - monomorphic e.g. pustules in steroid use
what is a papule?
a solid or cystic raised spot on the skin that is less than 1cm
what is a pustule?
small inflamed pus filled blister like sore on the skin surface
What is acne fulminans?
very severe acne associated with systemic upset (fever). Hospital admission is often required and the condition usually responds to oral steroids
How can acne be classified?
mild: open and closed comedones with or without sparse inflammatory lesions
moderate acne: widespread non-inflammatory lesions and numerous papules and pustules
severe acne: extensive inflammatory lesions, which may include nodules, pitting, and scarring
What is the mx for acne vulgaris?
1st = single topical retinoid or benzoyl peroxide
2nd = topical combination therapy with topical abx, benzoyl peroxide or topical retinoid
3rd = oral abx (tetracyclines = lymecycline, oxytetracycline or doxycycline) OR COPC in women + co-prescribe topical retinid/benzoyl peroxide (but not a topical abx)
4th = oral isotretinoin under specialist supervision
What tx for acne can you not give to pregnant women?
Retinoids
Tetracyclines - lymecycline, oxytetracycline or doxycycline. Use erythromycin instead
Oral isotretinoin
What are the complications of acne?
Post inflammatory lesions - scarring and hyperpigmentation
Mental health impact
What are some prognostic markers associated with severe eczema?
onset at age 3-6 months severe disease in childhood associated asthma or hay fever small family size high IgE serum levels
What is the Mx for eczema?
- emollients (E45, diprobase, oilatum, aveeno), soap substitutes
- topical steroids - hydrocortisone, eumovate, betnovate, dermovate
- UV radiation
- immunosuppressants: e.g. ciclosporin, antihistamines and azathioprine
What is eczema?
chronic atopic condition caused by defects in the normal continuity of the skin barrier, leading to inflammation in the skin.
Symptoms of eczema
Dry, red, itchy and sore patches on the skin
On flexor surfaces - inside the elbows and knees & face/neck
Have flares
Side effects of topical steroids
thinning of the skin = skin is more prone to flares, bruising, tearing, stretch marks and telangiectasia
What bacteria opportunistically infect the skin of patients with eczema?
Staph aureus (tx flucloaxacillin)
What is eczema herpeticum?
a viral skin infection in patients with eczema caused by the herpes simplex virus (HSV) or varicella zoster virus (VZV).
What is basal cell carcinoma?
One of the 3 main types of skin cancer
Lesions are slow growing and only locally invade, metastases are extremely rare
Lesions are called rodent ulcers
Symptoms of basal cell carcinoma
Sun exposed sites are affected - head & neck, not the ear
Initially are pearly flesh coloured papules with telangiectasia
They then may ulcerate, leaving a central crater
How should patients with suspected BCC be referred?
Routine referral
Mx of BCC
surgical removal curettage cryotherapy topical cream: imiquimod, fluorouracil radiotherapy
Do a punch biopsy if treatment other than standard surgical excision is planned
What are the subtypes of BCC?
Nodular
Morphoeic
Superficial
Pigmented
What is cellulitis?
an inflammation of the skin and subcutaneous tissues, typically due to infection by Streptococcus pyogenes or Staphylcoccus aureus.
What bacteria commonly cause cellulitis?
Strep pyogenes
Staph aureus
What are the symptoms of cellulitis?
Commonly occurs on the shins
Erythema, pain and swelling
systemic upset - fever
Ix for cellulitis
Clinical diagnosis
Can do bloods and blood cultures if sepsis is suspected
How can cellulitis be classified?
With Iron classification
I = no signs of systemic toxicity
II = systemically unwell / co-morbidity which may complicate or delay resolution
III = significant systemic upset (acute confusion, tachycardia, tachypnoea, hypotension) / unstable co-morbidity (vascular compromise of limb)
IV = sepsis syndrome or severe life threatening infection e.g. necrotising fasciitis
Who should be admitted for IV antibiotics with cellulitis?
Eron classification III or IV cellulitis
Severe/rapidly deteriorating cellulitis
<1yo / frail
Immunocompromised
Significant lymphoedema
Facial cellulitis or periorbital cellulitis
Mx of cellulitis
1) oral abx if Eron classification I or II: flucloxaccilin, clarithromycin, erythromycin (pregnancy) or doxycycline
2) IV abx in Eron classification III or IV: co-amoxiclav, cefuroxime, clindamycin or ceftriaxone
What are the 2 types of contact dermatitis?
Irritant contact dermatitis
Allergic contact dermatitis
What is irritant contact dermatitis?
common - non-allergic reaction due to weak acids or alkalis (e.g. detergents).
Often seen on the hands.
Erythema is typical, crusting and vesicles are rare
What is allergic contact dermatitis?
type IV hypersensitivity reaction.
Uncommon - often seen on the head following hair dyes.
Presents as an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself.
Topical treatment with a potent steroid is indicated
What is pityriasis versicolor?
Also called tinea versicolor
Is a superficial cutaneous fingal infection
What is the fungus that causes pityriasis versicolor?
Malassezia furfur
Symptoms of pityriasis versicolor
Most commonly affects trunk Patches are hypo pigmented, pink or brown More noticeable following a suntan Scale is common Mild pruritus
Risk factors for pityriasis versicolor
can occur in healthy individuals
Immunosuppression
Malnutrition
Cushings syndrome
Mx of pityriasis versicolor?
Topical anti fungal - ketoconazole shampoo
If it doesn’t respond - consider another diagnosis (send scrapings to confirm diagnosis) + oral itraconazole
What is the cause of cutaneous warts?
HPV
Symptoms of cutaneous warts
Commonly seen on hands and feet (verruca = plantar wart)
Firm raised, with a rough surface that resembles a cauliflower
Symptoms of lichen planus
itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
rash often polygonal in shape, with a ‘white-lines’ pattern on the surface (Wickham’s striae)
Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
nails: thinning of nail plate, longitudinal ridging
Mx of lichen planus
Topical potent steroids
Benzydamina mouthwash or spray
May need oral steroids or immunosuppression
Mx for cutaneous warts
Topical salicylic acid
Cryotherapy
Referral to dermatology for cutaneous warts if..
An uncertain diagnosis.
A facial wart.
Multiple recalcitrant warts and compromised immunity.
Extensive warts.
Persistent warts that are unresponsive to available primary care treatments.
What is folliculitis?
Localised inflammation of the hair follicle or sebaceous gland that is limited to the epidermis
What is hot tub folliculitis?
Pseudomonal folliculitis that appears 8-48 hours after exposure to contaminated water, is usually self limiting and doesn’t require abx
Symptoms of folliculitis
tender papules / pustules
Pruritic
Located at the site of hair follicles
What causes head lice?
the parasitic insect Pediculus capitis
What is the life cycle of head lice?
Head lice - only live on humans and feed on blood
Eggs - grey/brown, glued to hair close to snap. Hatch in 7-10 days
Nits - empty egg shells, white, shiny. found further along the hair shaft as they grow out
Symptoms of head lice
New cases have no symptoms
Itching occurs 2-3 weeks after infection
Diagnosis of head lice
fine-toothed combing of wet or dry hair
Mx of head lice
treatment is only indicated if living lice are found
a choice of treatments should be offered - malathion, wet combing, dimeticone, isopropyl myristate and cyclomethicone
household contacts of patients with head lice do not need to be treated unless they are also affected
No school exclusion advised
What is impetigo?
a superficial bacterial skin infection usually caused by either Staphylcoccus aureus or Streptococcus pyogenes.
symptoms of impetigo
‘golden’, crusted skin lesions typically found around the mouth
Tends to occur on the face, flexures and limbs not covered by clothing
very contagious
How is impetigo spread?
Direct contact with discharges from the scabs of an infected person
Indirect spread via toys, clothing, equipment and the environment can occur
what is the incubation period for impetigo?
4-10 days
Mx of impetigo
1) hydrogen peroxide 1% cream
2) topical abx creams: topical fusidic acid, topical mupirocin
3) oral flucloxacillin or erythromycin
Should children with impetigo be kept off school?
children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
What is malignant melanoma?
A malignant tumour arising from melanocytes in the skin
Risk factors for malignant melanoma
A personal/family hx of skin cancer Pale skin Hx of sunburn Hx of sun bed use Large number of moles Increasing age Organ transplant recipients
symptoms of malignant melanoma
Major features (2 points each):
- Change in size
- Irregular shape or border
- Irregular colour
Minor features (1 point each):
- Largest diameter 7mm or more
- Inflammation
- Oozing or crusting of the lesion
- Change in sensation (including itch)
Suspicion is greater for lesions scoring 3 points or more
Ix for malignant melanoma
Excision biopsy & histology
What are the types of malignant melanoma
Superficial spreading (most common type) - get on the arms, legs, back and chest in young people. Is a growing mole.
Nodular melanoma (second most common and most aggressive form) - sun exposed skin on middle aged people. Red or black lump or lump that bleeds/oozes
Lentigo melanoma - chronically sun exposed skin, older people. A growing mole
Acral lentiginous - a rare form. Nails, palms or soles. In African Americans or asians. Subungal pigmentation (Hutchinson’s sign) or on palms/feet
mx of malignant melanoma
Suspicious lesions = excision biopsy to completely remove lesion, histology
Once diagnosis is confirmed on histology, a report will say whether further re-exision of margins is required
Sentinel lymph node mapping
Isolated limb perfusion
Block dissection of regional lymph node groups
What predicts the prognosis of malignant melanoma?
Dependent on the stage which is assessed by the thickness, level of ulceration and spread to local lymph nodes
What predicts the prognosis of malignant melanoma?
Dependent on the stage which is assessed by the thickness (Breslow depth), level of ulceration and spread to local lymph nodes
What is erythema nodosum?
Inflammation of subcutaneous fat that causes tender, red, nodular lesions. Usually over the shins, forearms or thighs.
Resolves within 6 weeks, lesions heal without scarring.
Causes of erythema nodosum
infection -
streptococci
tuberculosis
brucellosis
systemic disease -
sarcoidosis
inflammatory bowel disease
Behcet’s
malignancy/lymphoma
drugs -
penicillins
sulphonamides
COPC
Causes of erythema nodosum
infection -
streptococci
tuberculosis
brucellosis
systemic disease -
sarcoidosis
inflammatory bowel disease
Behcet’s
malignancy/lymphoma
drugs -
penicillins
sulphonamides
COPC
Pregnancy
Mx of guttate psoriasis
Most cases resolve in 2-3 months without tx
Can use topical agents as per psoriasis
UBV phototherapy
tonsillectomy in recurrent cases
What is pyoderma gangrenosum?
Rare non infectious inflammatory disorder. Uncommon cause of very painful skin ulceration. Affects lower legs most commonly.
Causes of pyoderma gangrenosum
idiopathic in 50%
inflammatory bowel disease in 10-15% -
ulcerative colitis
Crohn’s
rheumatological -
rheumatoid arthritis
SLE
haematological - myeloproliferative disorders lymphoma myeloid leukaemias monoclonal gammopathy (IgA)
granulomatosis with polyangiitis
primary biliary cirrhosis
Symptoms of pyoderma gangrenosum
location:
- typically lower limb
- soften at the site of a minor injury
initially features:
- starts quite suddenly
- small pustule, red bump or blood-blister
later features:
- skin breaks down resulting in an ulcer which is often painful
- edge of the ulcer = purple, violaceous and undermined.
- the ulcer itself may be deep and necrotic
may be accompanied by systemic symptoms:
- fever
- myalgia
Mx of pyoderma gangrenosum
Oral steroids
Immunosuppression - ciclosporin / infliximab
What is psoriasis?
a common chronic skin disorder
Red scaly patches on the skin
causes of psoriasis
genetic: associated HLA-B13, -B17, and -Cw6.
immunological factors
environmental: it is recognised that psoriasis may be worsened (e.g. Skin trauma, stress), triggered (e.g. Streptococcal infection) or improved (e.g. Sunlight) by environmental factors
complications of psoriasis
psoriatic arthropathy (around 10%)
increased incidence of metabolic syndrome
increased incidence of cardiovascular disease
increased incidence of venous thromboembolism
psychological distress
symptoms of psoriasis
red, scaly patches on the skin
nail signs: pitting, onycholysis
arthritis
mx of psoriasis
regular emollients may help to reduce scale loss and reduce pruritus
first-line: NICE recommend:
a potent corticosteroid (betamethasone) applied once daily plus vitamin D analogue applied once daily (topical calcipotriol)
should be applied separately, one in the morning and the other in the evening)
for up to 4 weeks as initial treatment
second-line: if no improvement after 8 weeks then offer:
a vitamin D analogue twice daily
third-line: if no improvement after 8-12 weeks then offer either:
a potent corticosteroid applied twice daily for up to 4 weeks, or
a coal tar preparation applied once or twice daily
short-acting dithranol can also be used
secondary care mx for psoriasis
Phototherapy with UVB
Oral methotrexate / ciclosporin / oral isotretinoin / infliximab
what is squamous cell carcinoma?
a common variant of skin cancer. Metastases are rare but may occur in 2-5% of patients.
risk factors for SSC?
excessive exposure to sunlight / psoralen UVA therapy
actinic keratoses and Bowen’s disease
immunosuppression e.g. following renal transplant, HIV
smoking
long-standing leg ulcers (Marjolin’s ulcer)
genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism
tx of ssc?
Surgical excision with 4mm margins if lesion <20mm in diameter.
If tumour >20mm then margins should be 6mm.
Mohs micrographic surgery may be used in high-risk patients and in cosmetically important sites.
Histology of psoriasis
On histology, there is epidermal hyperplasia (acanthosis), hyperkeratosis with retention of nuclei in stratum corneum (parakeratosis) and groups of neutrophils in the stratum corneum (Munro microabscesses).
what is a mole?
a benign neoplasm of melanocytes
also called nevus
What are the 6 Ps of lichen planus?
Pruritic, purple, polygonal, planar papules and plaques
What is the mx for scalp psoriasis?
Potent topical corticosteroid for 4 weeks OD
If unsuccessful:
- Different formulation of potent corticosteroid e.g. shampoo/mouse
- Or topical agents to remove scale e.g. salicylic acid, emollients or oils before applying the steroid
warnings with topical steroids
may lead to skin atrophy, striae and rebound symptoms
the scalp, face and flexures are particularly prone to steroid atrophy so topical steroids should not be used for more than 1-2 weeks/month
systemic side-effects may be seen when potent corticosteroids are used on large areas e.g. > 10% of the body surface area
NICE recommend that we aim for a 4-week break before starting another course of topical corticosteroids
they also recommend using potent corticosteroids for no longer than 8 weeks at a time and very potent corticosteroids for no longer than 4 weeks at a time
Example vitamin D analogue
Calcipotriol
Can vitamin D analogues be used long term
YEs, unlike steroids
Can vitamin D analogues be used in pregnancy?
No, this should be avoided
What are the nail changes seen in psoriasis?
pitting
onycholysis (separation of the nail from the nail bed)
subungual hyperkeratosis
loss of the nail
What causes scabies?
the mite Sarcoptes scabiei
How is scabies spread?
By prolonged skin contact
Pathology of scabies infection
The scabies mite burrows into the skin, laying its eggs in the stratum corneum.
The intense pruritus associated with scabies is due to a delayed-type IV hypersensitivity reaction to mites/eggs which occurs about 30 days after the initial infection.
Symptoms of scabies
widespread pruritus
linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
in infants, the face and scalp may also be affected
secondary features are seen due to scratching: excoriation, infection
Mx of scabies
permethrin 5% is first-line
malathion 0.5% is second-line
give appropriate guidance on use - apply it to cool, dry skin. Apply all over including the face and scalp. Pay close attention to areas between fingers/toes, under nails, armpit areas. Leave to dry for 8-12 hours (permethrin) or 24 hours (malathion) before washing off. Repeat 7 days later
pruritus persists for up to 4-6 weeks post eradication
Avoid close physical contact until treatment is complete
All household and close physical contacts should be treated at the same time, even if asymptomatic
Lander, iron or tumble dry clothing, bedding and towels
what is Stevens-johnson syndrome?
a severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction.
Symptoms of Stevens-johnson syndrome
rash is typically maculopapular with target lesions being characteristic. May develop into vesicles or bullae
mucosal involvement
systemic symptoms: fever, arthralgia
Causes of Stevens-johnson syndrome
penicillin sulphonamides lamotrigine, carbamazepine, phenytoin allopurinol NSAIDs COCP
Mx of Stevens-johnson syndrome
hospital admission is required for supportive treatment
risk factors for Stevens-johnson syndrome
female
HIV
Mycoplasma / CMV
