Dermatology Flashcards
What is pemphigus vulgaris?
Autoimmune condition characterised by IgG antibodies against desmoglein 3
When does pemphigus vulgaris normally occur?
Middle age
What are risk factors for pemphigus vulgaris?
Jewish descent, drugs (NSAIDs, ACEis)
How does pemphigus vulgaris present?
Flaccid blisters that are easily ruptured to form shallow erosions. Not itchy. Seen in face, scalp, axilla, mucosa
Is pemphigus vulgaris Nikolsky sign +ve or -ve?
Positive
What does immunofluorescence of Pemphigus Vulgaris show?
Intracellular IgG deposits
‘Crazy paving/chicken wire appearance on immunofluorescence’
Pemphigus vulgaris
What is the treatment of pemphigus vulgaris?
Topical steroids and pain relief
Prednisolone +/- azaithioprine, dapsone, ciclosporin
What is the prognosis of pemphigus vulgaris?
Remits in 3-6 years, mortality rate of 10-20%
What is bullous pemphigoid?
Autoimmune condition characterised by antibodies against the BM
What age group commonly get bullous pemphigoid?
Elderly
How does bullous pemphigoid present?
Itchy tense bullae, around flexures, on an urticarial base. Usually without scarring, mouth spared
Is bullous pemphigoid Nikolsky sign +ve or -ve?
Negative
What is seen on immunofluorescence in bullous pemphigoid?
IgG and c3 deposits at dermoepidermal junction
How is bullous pemphigoid managed?
Topical steroids
Oral prednisolone, tetracyclines, azaithioprine, dapsone
What is the prognosis of bullous pemphigoid?
Chronic self limiting course, most achieve remission in 3-6 months
What is dermatitis herpetiformis?
Autoimmune blistering skin condition caused by IgA deposition in the dermis
What is dermatitis herpetiformis associated with?
Coeliac disease
How does dermatitis herpetiformis present?
Itchy, vesicular skin lesions on extensor surfaces, buttocks, face and scalp. On erythematous bases
What is seen on histology in dermatitis herpetiformis?
Papillary dermal microabscesses
IgA deposits in dermal papillae
How is dermatitis herpetiformis treated?
Gluten free diet
Dapsone, tetracyclines
What is acne vulgaris?
Common chronic inflammatory condition of the pilosebaceous unit
What percentage of teenagers does acne vulgaris affect?
80-90%
What are the 4 main pathogenesis’ of acne vulgaris?
Duct occlusion
Increased sebum production
Bacterial colonisation
Inflammation
What bacteria commonly colonise in acne vulgaris?
P. Acnes, staph epidermidis
What are aggravating factors for acne vulgaris?
Diet, premenstrual, sweating, UV radiation, job (Steam/oil), stress
What atrophic scarring is seen in acne vulgaris?
‘Ice pick lesions’
What hypertrophic scarring is seen in acne vulgaris?
Keloid
What is mild acne?
Scattered papules and pustules
What is moderate acne?
Numerous papules, pustules, atrophic scarring
What is severe acne?
Papules, pustules, nodules, significant scarring
What is the first line management of acne?
Single topical treatment
What topical treatments are there?
Topical antibiotics
Topical retinoids
Benzoyl Peroxide
What is second line management of acne?
Combined topical treatment
What is 3rd line management of acne?
Oral antibiotics or OCP
What oral antibiotics are used for management of acne vulgaris?
Erythromycin, oxytetracycle, lymecycline, doxycycline
What are side effects of oral antibiotics?
Gi upset, thrush, photosensivity
What type of COCP is used for acne vulgaris?
Dianette, triphasic pills
How will progesterone only contraception affect acne vulgaris?
May exacerbate it
What is 4th line acne treatment?
Oral retinoids
How doe oral isotretinoin (roaccutane) work?
Reduces sebaceous gland activity
What are side effects of roaccutane?
Dry skin, lips, eyes, skin fragility, hyperlipidaemia, abnormal LFTs, teratogenic, mood alteration, hair thinning,
What is acne rosacea?
Chronic skin condition of unknown aetiology
How does acne rosacea present?
papules, pustules and erythema, prominent facial flushing (worsened by spicy food/alcohol)
What is acne rosacea associated with?
Blepharitis
How is acne rosacea managed?
Avoid dietary triggers
Topical metronidazole
Telangactasia - laser therapy
Rhinophyma - surgery/laser shaving
What is eczema?
Inflammatory skin condition often starting in early infancy
What are causes of eczema?
Multifactorial - genetics, allergens, diet, overwashing, poor barrier, filaggrin deficiency, dryness, heat, cold, stress, infection
Which social class is there a higher incidence of eczema in?
Higher social classes
How does eczema present?
Itchy, red, flexural rash. Chronic scratching causes lichenification, scarring, infection
How is eczema diagnosed?
Itching PLUS 3 OF
visible flexural rash, history of flexural rash, personal/family history of atopy, dry skin, onset before 2
What is step 1 in eczema management?
Emollients
What is step 2 in eczema management?
Emollients + mild steroid
What is step 3 in eczema management?
Emollients + mild steroid + calcineurin inhibitor
What is step 4 in eczema management?
Emollients + potent/very potent steroid
How should emollients be used?
Liberally (500g/week), also bath and shower emollients
What are the effects of topical steroids?
Anti-inflammatory
Vasoconstrictive
Antiproliferative
What are side effects of topical steroids?
Skin thinning, increased infections, telangastasia, cushings
How much steroid does one finger tip unit cover?
Two hands
What is an example of a mild topical steroid?
Hydrocortisone
What is an example of a moderate topical steroid?
Eumovate
What is an example of a potent topical steroid?
Betnovate
What is an example of a very potent topical steroid?
Dermovate
What are examples of calcineurin inhibitors?
Tacrolimus, pimecromilus
What can be used if eczema is severe and does not respond to topical treatments?
Phototherapy, systemic agents (e.g. azaithioprine, methotrexate, mycopentolate)
What organism is the cause of infected eczema?
Staph Aureus
How is infected eczema treated?
Fusidic acid
What is eczema herpeticum?
Herpes simplex infection of eczema
How does eczema herpeticum present and how is it treated?
Monomorphic rash with circular blisters
EMERGENCY - admit for IV aciclovir
What is psoriasis?
Chronic relapsing remitting condition
When is the peak incidence of psoriasis?
20s-50s
What is the underlying pathophysiology of psoriasis?
Hyperproliferation of epidermal cells
What is the normal skin turnover?
25 days ish
What is the skin turnover in psoriasis?
5 days
What does histology show in psoriasis?
Parakeratotic statum corneum
Absence of granular layer
Extended prickle cell layer
How does chronic plaque psoriasis present?
Erythematous, scaly plaques on extensor aspects of skin. Palpable and shiny with silvery scale. Koebner phenomenon
What is the Koebner phenomenon?
Skin lesions arising in areas of trauma
How does guttate psoriasis present?
Usually occurs 2-4 weeks post strep infection. ‘Tear drop’ scaly patches. Resolves spontaneously in 2-4 months
How does flexural psoriasis present?
Shiny red well demarcated plaques in flexural surfaces
How does erythrodermic psoriasis present?
90% of skin surface goes red. Usually occurs in patients with psoriasis and is due to UV burns/withdrawal of steroids
What nail changes may be seen in psoriasis?
Pitting, onycholysis, oil drop lesions, sublingual hyperkeratosis, deformity
How is psoriasis managed 1st line?
Topical treatment
What topical treatments are available for psoriasis?
Emollients, tar, vitamin D analogues, salicylic acid, dithranol, steroids