Dermatology Flashcards
What is the classic presentation of a dermoid cyst?
= cystic teratoma - tumour of mature skin cells; contains skin, sweat glands, hair follicles; sometimes teeth, fat, bone, thyroid tissue. commonly occurs in young child at lateral aspect of eyebrow
What investigation might be required for dermoid cysts and why?
if appears close to midline - to look for intracranial extension if excision considered
What are the commonest histological findings in seborrhoeic keratosis?
localised proliferation of basal layer of epidermis
What are the characteristic features of a sebaceous cyst?
considered same as epidermoid cyst (type of trichilemmal cyst) - closed sac/cyst with lining resembling upper part of hair follicle, produces sebum, may have visible punctum
What is the management of the following manifestations of herpes simplex virus?
- gingivostomatitis: oral aciclovir, chlorhexidine mouthwash
- cold sores: topical aciclovir (?limited benefit)
- genital herpes: oral aciclovir
What is the guidance for herpes simplex infection during pregnancy?
- elective caesarean if primary attack of herpes >28 weeks gestation
- pregnant + BG recurrent herpes: suppressive therapy, reassure low risk of fetal transmission
What organism causes pityriasis versicolor?
Malassezia furfur
What are the features of pityriasis versicolor?
- red when occur in white skin, paler than surrounding skin on brown/black skin
- more noticeable following sun tan
- scale common
- may be itchy
What is first line treatment for pityriasis versicolor?
ketoconazole shampoo - useful for covering large surface area of body
What viruses causes Kaposi’s sarcoma?
Human herpes virus 8
What is the treatment of kaposi’s sarcoma?
radiotherapy + resection
Do most melanomas arise in normal skin or pre-existing moles?
most in normal skin
What is the treatment of acute urticaria?
- First line - non-sedating antihistamine (cetirizine, loratidine, fexofenadine)
- if inadequate response to treatment - doubel standard dose of antihistamine / switch to alternative / use sedating AH at night
- If severe/resistant - prednisolone + AH
What makes incisions less likely to cause keloid scars?
Making incisions along relaxed skin tension lines
What are two options for the treatment of keloid scars?
Intra-lesional steroids e.g. triamcinolone injection
Excision - but be wary may create more scars
What treatment options exist for a port wine stain?
cosmetic camouflage or laser therapy
What are 3 genetic factors that play a role in psoriasis?
- HLA-B13
- HLA-B17
- HLA-Cw6
What immunological factors play a role in psoriasis?
T helper cells, Th17, which produce IL-17 - stimulates keratinocyte proliferation
What is the most common subtype of psoriasis?
plaque psoriasis
What are 4 types of psoriasis?
- plaque psoriasis
- flexural psoriasis (smooth)
- guttate psoriasis (triggered by strep)
- pustular psoriasis (palms + soles)
What are the diagnostic criteria for malignant melanoma?
Glasgow 7 -
3 major: change in size, shape and colour
4 minor: diameter >7mm, inflammation, oozing/bleeding, itch/ odd sensation
What are the commonest sites for melanoma in males vs females?
Males - trunk
Females - lower leg
What 2 dermatological side effects may be seen on the face from anabolic steroids?
- acne conglobata - severe form of acne with burrowing + interconnecting abscesses, irregular scars (keloidal and atrophic)
- acne fulminans - severe, painful, haemorrhagic acne
What are 6 treatment options for actinic keratoses?
- Topical fluorouracil (2-3 week course)
- Topical diclofenac
- Imiquimod
- Cryotherapy
- Curettage
- Cautery
What are 6 types of drugs which can exacerbate plaque psoriasis?
- Beta blockers
- Lithium
- ACE inhibitors
- NSAIDs
- Antimalarials - chloroquine and hydroxychloroquine
- Infliximab
What are 3 non-drug causes which can exacerbate plaque psoriasis?
- Alcohol
- Trauma
- Withdrawal of systemic steroids
When does BCC require referral to dermatology on 2ww?
If in areas at high risk of causing damage - eyelids, nasal ala
otherwise routine
What are 6 management options for BCC?
- Surgical removal
- Radiotherapy
- Cryotherapy
- Curettage
- Fluorouracil
- Imiquimod
What is the autoimmune process happening in bullous pemphigoid?
antibodies to hemidesmosome proteins BP180 and BP230 - causes subepidermal blistering
What are 3 features of blistering disease in bullous pemphigoid?
- itchy, tense blisters around flexures
- blisters heal without scarring
- in exams: no mucosal involvement
How should bullous pemphigoid be managed if suspected in primary care?
refer to secondary care (dermatology)
How is bullous pemphigoid investigated?
- skin biopsy
- histopathological examination + immunofluorescence testing
What does immunofluorescence testing show in bullous pemphigoid?
IgG and C3 at the dermoepidermal junction
What is the treatment of bullous pemphigoid?
mainstay = oral corticosteroids; topical steroids, immunosuppressants, antibiotics also used
What is the approximate risk of someone having another seizure after a first episode unprovoked seizure with normal investigations?
30-50%
70-80% after second unprovoked seizure - as suggests epilepsy
In what proportion of dermatomyositis is there associated underlying malignancy?
20-25%
What are 3 types of malignancy associated with dermatomyositis?
- Ovarian
- Breast
- Lung cancer
What is polymyositis?
variant of dermatomyositis where skin manifestations are not prominent
What are 5 less common features of dermatomyositis?
- proximal muscle weakness +- tenderness
- raynaud’s
- respiratory muscle weakness
- ILD e.g. fibrosing alveolitis or organising pneumonia
- dysphagia, dysphonia
What are are 4 types of blood tests which may be positive in dermatomyositis?
- ANA positive (80%)
antibodies to aminoacyl-tRNA synthetases including:
1. anti-tRNA ligase aka Jo-1
2. anti-signal recognition particle (SRP)
3. anti-Mi-2
What are 8 complications of extensive burns?
- haemolysis due to damage of erythrocytes by heat and microangiopathy
- loss of capillary membrane integrity causing plasma leakage into interstitial space
- extravasation of fluids from burn site causing hypovolaemic shock
- protein loss
- secondary infection e.g. Staph aureus
- ARDS
- Curlings ulcer
- compartment syndrome - full thickness circumferential burns in an extremity
What is the method of healing for superificial burns?
kertinocytes migrate to form a new layer over burn site
What is the method of healing of full thickness burns?
dermal scarring; need keratinocytes from skin grafts to provide optimal coverage
What are the 3 criteria that must be met for post-exposure prophylaxis treatment for VZV?
- significant exposure (if limited, covered up shingles doesn’t count)
- clinical condition increasing risk of severe varicella - immunosuppressed, neonates, pregnant
- no antibodies
What timing should be met for blood tests for varicella antibdies in PEP for VZV?
ideally all patients should have blood test, bus shouldn’t delay post-exposure prophylaxis past 7 days after initial contact
What treatment is given for post-exposure prophylaxis for VZV if they meet the criteria?
varicella zoster immunoglobulin
What is the usual age of onset of vitiligo?
20-30 years
Which areas tend to be most affected by vitiligo?
Peripheries
What are 4 aspects of management of vitiligo?
- Sun block
- Camouflage makeup
- Steroids if applied early
- Tacrolimus + phototherapy may have role
How are fracture NOFs divided anatomically?
- intracapsular
- extracapsular - divided into trochanteric and subtrochanteric
What is granuloma annulare?
papular lesions that are often sligthyl hyperpigmented and depressed central
Where does granuloma annulare most commonly occur?
dorsal surfaces of hands and feet, and extensor aspects of arms and legs
What is a possible association of granuloma annulare?
diabetes mellitus (weak evidence)
What are 7 systemic disease causes of pruritus?
- Liver disease
- Iron deficiency anaemia
- Polycythaemia
- Chronic kidney disease
- Lymphoma
- Hyper/hypothyroidism
- Diabetes
What is the causative organism of molluscum contagiosum?
MCV, a member of Poxviridae family
In which patient group does molluscum contagiosum most commonly occur?
children (often with atopic eczema)
What is the prognosis of molluscum contagiosum?
spontaneous resolution usually occurs within 18 months; self-limiting condition
What are 3 types of treatment, if required, for molluscum contagiosum?
- squeezing (fingernails) or piercing (orange stick) may be tried, following bath (a few lesions at a time only)
- cryotherapy - by experienced HCP
- if eczema/inflammation around lesions - emollient + mild topical corticosteroid for itch, topical abx if looks infected e.g. fusidic acid
What are 3 situations when referral is required for molluscum contagiosum?
- HIV positive + extensive lesions - HIV specialist (URGENT)
- eyelid-margin or ocular lesions + red eye - ophthalmology (URGENT)
- anogenital lesions - GUM for STI screening
What is the presentation of acne rosacea?
- flushing of nose, cheeks, forehead
- telangiectasia
- later develops into persistent erythema + papules + pustules
- rhinophyma, blepharitis
What are 4 things that can trigger / exacerbate symptoms of acne rosacea?
- alcohol
- spicy foods
- hot drinks
- sunlight
What are 4 aspects of the management of acne rosacea?
- sunscreen, camouflage creams
- topical brimonidine - for predominant flushing
- topic ivermectin - for mild-moderate papules/pustules
- topical ivermectin + oral doxycycline - moderate-severe papules / pustules
How quickly does topical brimonidine work to treat flushing in acne rosacea?
reduces redness within 30 minutes, reaches peak action at 3-6 hours, then redness returns
What are 2 second-line alternatives to topical ivermectin for mild-moderate papules/pustules in acne rosacea?
topical metronidazole, topical azelaic acid
What are 2 organisms which most commonly cause cellulitis?
- Streptococcus pyogenes
- Staphylococcus aureus
What classification is used for cellulitis to guide management and what are the classes?
Eron classification
1. No signs of systemic toxicity, no uncontrolled comorbidities
2. systemically unwell or systemically well with comorbidity (e.g. PAD, chronic venous insufficiency, morbid obesity)
3. significant systemic upset e.g. acute confusion, tachycardia, tachypnoea, hypotension, or unstable comorbidities
4. sepsis syndrome or severe life-threatening infection e.g. necrotising fasciitis
What are 6 criteria recommended by NICE for admission for IV treatment of cellulitis?
- Eron class III or IV
- severe or rapidly deteriorating cellulitis (e.g. extensive areas of skin)
- very young (<1year) or frail
- immunocompromised
- significant lymphoedema
- facial cellulitis or periorbital cellulitis
Which antibiotics can be given in cellulitis, Eron grade I-II in penicillin allergic patients?
clarithromycin, erythromycin (pregnancy), doxycycline
flucloxacillin normally first line
What is the recommended management of Eron grade III-IV cellulitis?
- admit
- oral/IV co-amoxiclav, oral/IV clindamycin, IV cefuroxime or IV ceftriaxone
What 3 groups can urticaria be classed into?
- idiopathic (30-40%)
- immunological: autoimmune, allergic, immune complex, complement-dependent
- non-immunological: drugs, dietary pseudoallergens
What are 4 types of immunological urticarias?
- autoimmune - autoantibodies against FcεRI or IgE
- allergic - IgE mediated type I
- immune complex (urticarial vasculitis)
- complement-dependent (c1 esterase inhibitor deficiency)
What are 4 drugs that can cause non-immunological urticaria?
- direct mast cell-releasing agents e.g. opiates
- aspirin
- NDSAIDs
- ACE inhibitors
When should patients with urticaria be referred to secondary care?
refer to a dermatologist or immunologist if symptoms are not well-controlled on treatment, or antihistamines required continuously for >6 weeks to control sx
What is the recommended management of a first presentation of alopecia areata?
topical corticosteroid + refer to dermatologist
What is the presentation of alopecia areata?
localised, well-demarcated patches of hair loss; at edge there may be exlamation mark hairs
What is the prognosis of alopecia areata?
hair will regrow in 50% of patients by 1 year, and 80-90% of patients eventually
What are 7 treatment options in alopecia areata?
- watchful waiting
- topical or intralesional corticosteroids
- topical minoxidil
- phototherapy
- dithranol
- contact immunotherapy
- wigs
What are the 2 types of necrotising fasciitis?
- type 1 caused by mixed anaerobes and aerobes (post surgery in diabetics)
- type 2 caused by Streptococcus pyogenes
Which type of necrotising fasciitis is more common?
type 1
Which patient group is more typically affected by type 1 necrotising fasciitis?
post-surgery in diabetics
What are 5 risk factors for necrotising fasciitis?
- skin factors: trauma, burns, soft tissue infections
- diabetes mellitus
- diabetic treated with SGLT2 inhibitors
- IV drug use
- immunosuppression
What is the body site most commonly affected by necrotising fasciitis?
perineum (Fournier’s gangrene)
What are the clinical features of necrotising fasciitis?
- acute onset
- pain, swelling, erythema
- may present as rapidly worsening cellulitis, POOP with physical features
- extreme tenderness
- hypoaesthesia to light touch
- skin necrosis + crepitus/gas gangrene - late
- fever and tachycardia
What is the management of necrotising fasciitis?
urgent surgical referral for debridement, IV antibiotics