Dermatology Flashcards
Risk factors/triggers/exacerbating factors for psoriasis
- Ethnicity - lower rates in Africans, Norwegians and some Asians
- Age - peaks in teenage/young adults and 50-60s
- Strep throat infection
- Other infections e.g. HIV
- Drugs e.g. lithium, beta-blockers, interferon-alpha, chloroquine
- Bone marrow transplant
- Obesity
- Smoking
- Alcohol
- Koebner phenomenon
- Psychogenic factors e.g. stress
Two cardinal histological features of psoriasis
1) Epidermal hyper proliferation
2) Pronounced inflammatory infiltrate
Clinical features of stable chronic plaque psoriasis
- Scaly, red well demarcated plaques
- Most commonly seen on extensor surfaces
- Remitting and relapsing course
- May be associated with psoriatic arthritis
- Increased risk of metabolic syndrome and CVD
Clinical features of guttate psoriasis
- Several hundred small lesions
- Most common on the trunk
- Most common in children and young adults
- 2-3 weeks after strep throat
Psoriatic nail signs
- Nail plate pitting
- Onycholysis
- Oily spots
How would you diagnose psoriasis
- Clinical diagnosis
Management of psoriasis
1) Avoidance of precipitants e.g. smoking cessation, reduce alcohol intake
2) Topical emollients
3) Topical corticosteroids (particularly in flexure and scalp psoriasis)
4) Topical vitamin D analogues
5) Phototherapy
5a) Narrow band UVB phototherapy (works best for small plaque psoriasis)
5b) PUVA therapy
6) Methotrexate
7) Ciclosporin
8) Retinoids (vitamin A analogues)
9) Biologics e.g. TNFa inhibitors or cytokine pathway inhibitor
Side effects of topical corticosteroids
- Skin thinning
- Telangiectasia
- Striae
- Systemic steroid effects with prolonged use
- May loss efficacy over time
Side effects of UBV phototherapy
- Small risk of sunburn
- Potential long-term increased risk of non-melanoma skin cancer
Side effects of PUVA therapy
- Tan
- Increased risk of non-melanoma and melanoma skin cancers
Side effects of methotrexate
- Hepatic fibrosis
- Bone marrow inhibition
- Immunosuppression
- Nausea
- Teratogenic - wait 3 months after stopping treatment two conceive
Monitoring required for patients on methotrexate
- Regular FBC, LFTs and U&Es
Side effects of ciclosporin
- Excessive hair growth
- Gingival hyperplasia
- Immunsuppression
- Nephrotoxicity
- Hypertension
- Increased risk of virally-associated cancers e.g. EBV-lymphoma, HPV-cervical cancer
Side effects of retinoids
- Teratogenic - women should not conceive for 3 years after treatment with acitretin
- Triglyceride elevation
- Increased CVD risk
- Mucosal and cutaneous dryness
- MSK pain
Side effects of biologics
- Immunosuppression
- Virus reactivation
- Worsening of inflammatory disease
3 pathogenic features of acne vulgaris
1) Abnormal keratinisation of the follicular epithelium
2) Increased sebum excretion
3) Infection with gram-positive rod Propionibacterium Acnes
Risk factors for acne
- Male sex
- PCOS
- Congenital adrenal hyperplasia
- Androgen secreting tumour
- Exogenous androgens e.g. steroids
- Family history
Clinical features of acne
- Typically affects the face and upper torso/back
- Includes: comedones, inflammatory papules, pustules, scars
- May have features of hyper-androgenism e.g. hirsutism, androgenic alopecia
Investigations to consider in a patient with acne
- Menstrual history
- Total and free testosterone
- DHEAS
- 17-hydroprogesterone
Management options for acne
1) Topical retinoids (best for comedonal acne)
2) Topical benzoyl peroxide
3) Topical or systemic antibiotics (tetracyclines, erythromycin, clindamycin)
4) Hormonal methods in women e.g. COCP
5) Systemic retinoids (4 month course, dose depends on weight)
Side effects of topical retinoids
- Mild inflammatory reaction e.g. erythema, dryness, scaling
- Teratogenic
Side effects of topical/systemic antibiotics in acne treatment
- Need to be tried for 2 months before considered ineffective
- Tetracyclines CI in <12s - stain teeth and absorbed by bone
- Teratogenic
What tests need to be done before starting a patient on isoretinoin?
- FBC
- Lipid profile
- TFTs
- Pregnancy test
Monitoring required whilst on isoretinoin
- Pregnancy test every month
- Pregnancy test 5 weeks after stopping
Side effects of isoretinoin
- May precipitate acne fulminas/temporary worsening of acne
- Teratogenic - need to use 2 methods of contraception and not conceive for 5 weeks after stopping treatment
- Increased triglycerides and cholesterol
- Abnormal LFTs
- Chelitis
- Dry eyes
- Dry nose and nosebleeds
- Dry skin
Management options for acne scarring
- Dermabrasion
- Carbon dioxide laser resurfacing
- Excision of small scars or cystic lesions
- Punching out or grafting ice-pick scars
- Fillers
- Potent peels (alpha-hydroxy acids)
Management of urticaria
- Non-sedative anti-histamines e.g. fexofenadine, cetirizine
4 autoimmune conditions associated with chronic symptoms urticaria
- Thyroid disease
- Vitiligo
- Rheumatoid arthritis
- Pernicious anaemia
Name 5 types of physical urticaria
- Dermographism
- Solar urticaria
- Cold urticaria
- Cholinergic urticaria
- Aquagenic urticaria
Management of angioedema
- C1-esterase inhibitors
- SC Icatibant (bradykinin B2 receptor antagonist)
Clinical features of anaphylaxis
- Vasodilation
- Hypotension
- Bronchoconstriction
- Circulatory collapse
Management of anaphylaxis
- IM adrenaline
- Oxygen
- IV fluids
Most common inflammatory skin condition
Eczema
Two pathological processes in eczema
1) Abnormal/inappropriate immune system behaviour
2) Compromised skin barrier function
Cardinal pathological features of eczema
- Intercellular epidermal oedema (spongiosis)
- Lymphoid infiltrates in the dermis and epidermis
- Acanthosis
- Hyperkeratosis
Exacerbating factors for atopic eczema
- Stress
- Dry skin
- Skin infection
- Certain foods
- Winter
- Skin irritation
- Hormones e.g. menstruation
Clinical features of atopic eczema
- Itchy, scaly rash on face at 6-12 months old
- Rash involves flexor surfaces
- Excoriations
- Skin weeps in flexures and feels rough and dry everywhere else
- Soap and detergents worsen symptoms
- Associated hay fever and asthma
- Lichenification
- Pityriasis alba
- Dennie-Morgan folds
- Increased peri-orbital pigmentation
- Chellitis
- Symptoms/signs of other atopic conditions e.g. sneezing, lacrimation, wheeze
Management of atopic eczema
1) Topical emollients
2) Topical antiseptics
3) Bandaging
4) Topical corticosteroids
5) Phototherapy - UVB or PUVA
6) Systemic immunosuppression
Biggest risk factor for contact irritant dermatitis
Atopic eczema
Differences between contact allergic dermatitis and contact irritant dermatitis
Contact irritant dermatitis has:
- no period of sensitisation
- dose dependent response
What type of hypersensitivity reaction is contact allergic dermatitis?
Type 4
Clinical features of contact allergic eczema
- Eczema symptoms develop 24-96 hours after exposure to antigen
- Erythema and induration
- Weeping vesicles and blister formation
- Itch
- Acanthosis and hyperkeratosis in prolonged reactions
Investigation of choice for contact allergic dermatitis
- Patch testing - suspected antigens applied to patient’s back then removed 24 hours later. Patient’s skin examined at 48-96 hours.
Clinical features of pemphigoid
- Usually >60s
- Itchy urticated lesions which precede blister formation by several months
- Large, tense, robust fluid-filled blisters
- Less mucosal involvement than pemphigus
Investigations and results in pemphigoid
- Blister biopsy: eosinophil rich inflammatory infiltrate and sub-epidermal blisters
- Immunofluorescence: IgG staining along basement membrane
Management of pemphigoid
1) Systemic corticosteroids +/- azathioprine
2) Other immunosuppressants
3) IV immunoglobulin, anti-CD20 antibodies or cyclophosphamide
Clinical features of pemphigus
- Superficial blisters (may have burst or crusted)
- Mucosal involvement - most patients have painful mouth erosions
- Positive Nikolsky sign (if you rub normal skin a blister will appear)
Investigations and results in pemphigus
- Biopsy: acantholysis
- Immunofluorescence: IgG intercellular staining
Management of pemphigus
1) High dose systemic corticosteroids
2) Azathioprine or mycophenolate
3) IV immunoglobulin, anti-CD20 antibodies or cyclophosphamide
Clinical features of dermatitis herpetiformis
- Intense, burning itch
- Small clusters of vesicles present on wrist, extensor surfaces of elbows and knees, sacrum and buttocks
- NO mucosal involvement
Investigations and results in dermatitis herpetiformis
- Biopsy: small polymorph abscess in the upper dermis
- Immunofluorescence: granular deposition of IgA in the dermis papillary tips
- TTG antibodies (80% of patients)
Management of dermatitis herpetiformis
1) Gluten free diet
2) Dapsone
Important side effects of dapsone
- Haemolytic anaemia
- Agranulocytosis
Clinical features of erythema multiforme
- <40s
- Males more commonly affected
- History of previous infection
- TARGET LESIONS (red/ducky cyanotic middles with bright erythematous outer ring) - initially macular but may become papular. May be haemorrhage or blistering at the centre.
- Rash most common on extremities e.g. hands, feet, face, elbows, knees
- Mucosal involvement may occur
- Fever and joint pain may occur
2 causes of erythema multiforme
- HSV
- Mycoplasma
Management of erythema multiforme
1) Basic skin care with antiseptics
2) Topical steroids
- IV fluids in those with severe mucosal involvement
- Ophthalmology assessment in eye involvement
How long after starting a drug will TEN commence?
7-28 days
Main risk factor for TEN
- Immunosuppression
Clinical features of TEN
- Elderly patient
- Sudden onset of diffuse erythema with sheets of skin undergoing necrosis
- Excruciatingly painful
- Mucosal involvement likely e.g. mouth, eyes, genitals
- Wrinkling/blistering under sheets of skin
- Nikolsky sign positive
- Systemic features e.g. pyrexia, malaise, dysuria, sore eyes may precede rash
- Often worse on the trunk
Definition of Steven-Johnson Syndrome
<10% of body area involvement (+ mucosal involvement)
Differentials for positive Nikolsky sign
- Pemphigus
- TEN
- SSSS
Management of TEN
- Stop relevant drugs ASAP
- Monitor fluid balance
- Adequate analgesia
- Controlled pressure thermo-regulated bed and aluminium survival sheet
- Ophthalmology assessment
Potential drug causes of TEN
- Allopurinol
- Carbamazepine
- Sulphonamides
Clinical scoring system used to predict prognosis of TEN
- SCORTEN
A SCORTEN score >? predicts death in 90% of cases
5
Main causes of death in TEN
- Infection
- Hyper-catabolic state
Clinical features of SSSS
- NO MUCOSAL INVOLVEMENT
- Usually children <5 (or immunosuppressed adults/adults with renal failure)
- Onset is a scarlet fever like rash around mouth and nappy area with peri-oral crusting and furrowing
- Erythema first appears on face then generalises
- Child is pyrexial but often systemically well
- Intense pain
- Over 48 hours, widespread blisters occur
- May be Nikolsky sign positive
Investigations to consider in suspected SSSS?
- Superficial skin biopsy
- Culture swabs from throat and eyes
Management of SSSS
- IV Flucloxacillin and Vancomycin
- Supportive care
- Barrier nursing
Causes/associations of leucocytoclastic vasculitis
- Infection e.g. Hep A, B or C, streptococci or mycobacterium
- Drugs e.g. beta blockers, penicillin, thiazide diuretics
- Malignancy e.g. CLL, lymphoma, myeloma
- Small vessel vasculitis
- Systemic disease e.g. IBD, sarcoidosis, Behcet’s