Dermatology COMPLETE Flashcards
REVIEWED ON 02/03/05
Dermatitis can be classed as endogenous and exogenous. Give examples for each.
Endogenous:
Atopic
Seborrhoeic
Venous
Exogenous:
Contact allergic / irritant
Photosensitive
Yeast responsible for seborrhoeic dermatitis, and who is at highest risk of this?
Malassezia furfur / pitysporum ovale
Associated with HIV and Parkinson’s disease
Babies vs children vs adults distribution of eczema:
Babies:
Face
Scalp
Arms
Legs
Children:
Starting to get it in flexures
Adults:
Flexure sites
Hands
Neck
General measure for eczema include avoiding irritants, frequent emollients, bandages and soap substitutes. What is used for active areas, and what different strengths are they?
Topical steroids:
Hydrocortisone 0.5-2.5%
Eumovate (clobestasone butyrate 0.05%)
Betnovate (betamethasone 0.1%)
Dermovate (clobestasone propionate 0.05%)
What can be used long term topically as a steroid sparing agent in eczema?
Tacrolimus topical
3 types of oral therapy sometimes used in eczema and when?
Antibiotics - superimposed bacterial infection
Antivirals - superimposed viral infection e.g. HSV1
Antihistamines - for itch
What are specialist options used in severe, non-responsive cases of eczema?
Phototherapy - UVA and B, reduces number of t cells which mediates the inflammation.
Immunosuppressants e.g. ciclosporin
Exacerbating factors in psoriasis:
Trauma
Alcohol
Drugs inc BB, lithium, antimalarials, NSAIDs and ACEi
Withdrawal of systemic steroids
Strep infection for guttate psoriasis
What is going wrong in psoriasis?
Psoriasis is a t cell autoimmune disease with abnormal infiltration of T cells that release inflammatory cytokines.
Increased keratinocyte proliferation leads to scaling and crusting.
Types of psoriasis, in order of most to least common.
Plaque
Guttate
Pustular
Erythrodermic
What often triggers guttate psoriasis?
Streptococcal infection
What is the Auspitz sign?
Plaques flaking off and causing pinpoint bleeding
Give some nail changes in psoriasis.
Pitting
Ridging
Thickening
Onycholysis - coming off of the nail bed
What is Koebner’s phenomenon?
Development of psoriatic lesions in areas of skin trauma.
3 systemic diseases / conditions associated with psoriasis:
Psoriatic arthritis
Metabolic syndrome
IBD
First line for psoriasis management:
Potent steroids OD + Vitamin D analogue OD for 4 weeks. One evening, one night
Second line for psoriasis management:
Add BD vitamin D topical to the potent topical steroid,
Third line for psoriasis managment:
If third line not working after 8-12 weeks since starting treatment, add potent steroids BD, or coal tar.
Specialist input options for psoriasis management:
Narrow band UVB three times per week if that hasn’t worked
Psoralen + UVA light (photochemotherapy)
What is the action / benefit for each of the following topical therapies; emollient, steroid, salicylic acid, vitamin D analogue.
Emollient - stops skin from drying out
Steroid - reduces autoimmune response and therefore inflammation
Salicylic acid - breaks down hard thick dead skin
Vitamin D analogue - slows down keratinocyte proliferation
Bacteria associated with colonisation in acne?
Proprionibacterum acnes
Complication of long-term antibiotic use in acne (rare) and how to treat it?
Gram negative folliculitis
High dose trimethoprim
Why are oral anti-androgens sometimes used in females for acne?
Reduce sebum production
Most common and least dangerous malignant skin cancer:
BCC
What is the most common type of BCC, and what kind of referral should be made if it is suspected?
Nodular - rolled, pearly edge.
Routine referral, does not need to be urgent.
Pre-malignant lesions for SCC and treatment:
Actinic keratoses ‘sun spots’, flat macules
Bowen’s disease - more crusty, red lesions.
Treat with flurouracil
Which cells are affected in SCC?
Epidermal keratinocytes
Risk factors for SCC:
UV exposure
Type I/II skin
Smoking
Increasing age
Burns or chronic inflammation e.g. Marjolin’s ulcer
Genetic
Immunosuppression
In skin types V and VI, which is the most common skin cancer?
SCC
Melanoma is an invasive malignant tumour of the epidermal melanocyte. What are the 4 types?
Superficial spreading - legs. Spread horizontally first, then invasive.
Nodular - trunk. Aggressive and metastasise early.
Lentigo maligna - age spots turn malignant. Face .
Acral - hands and feet, nail beds. Most common type in skin of colour.
What is the ABCDE assessment tool in dermatological examination? Which ones are the most likely to be suspicious in melanoma?
Asymmetry
Border
Colour variation
Diameter >6mm?
Evolution / growth
Assymetry, colour variation, evolution.
What system is used to predict 5 year mortality from malignant melanoma?
Breslow thickness
<0.75 95-100%
0.75-1.5 80-96%
1.5-4 60-75%
>4 50%
TEN vs SJS in terms of body surface area? Management?
SJS <10%
TEN >30%
Both require admission to burn units.
Ig FIRST LINE
Supportive Mx, ICU? Fluids, ciclosporin, plasmapharesis
SJS = mucocutaneous necrosis with ad least 2 mucosal sites involved.
TEN includes systemic toxicity.
Type of reaction in SJS/TEN?
Type IV hypersensitivity reaction - delayed
SJS / TEN most commonly caused by drug reactions and have a flu like prodrome. Which drugs?
Drugs:
Antibiotics especially beta lactams e.g. penicillins, cephalosporins.
Allopurinol
Carbamazepine and phenytoin
Sulfasalazine
All Antibiotics Can Present Severe !
What is Nikolsky’s sign?
Mild lateral pressure causes separation of the epidermis.
Most common cause of erythema multiforme, and clinical features?
HSV1
Coin / target lesions, developing peripherally and spreading to torso.
Self limiting in 4-6 weeks.
Erythema nodosum presents with:
Inflammation of subcutaneous fat.
Painful red nodules, anterior shin.
Causes / risk factors for erythema nodosum:
Infection esp TB, chlamydia and strep throat
Pregnancy
Inflammatory e.g. IBD, sarcoidosis
3 cutaneous complications / manifestations of diabetes mellitus (type 2):
Leg ulcer
Foot ulcer
Acanthosis nigricans (insulin resistance)
Hyper vs hypothyroid cutaneous manifestations:
Hypothyroid - dry skin, loss of outer 1/3 of eyebrow, coarse rough skin
Hyperthyroid - Grave’s eye disease, pretibial myxoedema, nail changes, hyperhidrosis, facial flushing, diffuse alopecia
A patient with a leg ulcer described that it is more painful when lying down than when upright and walking. What type of ulcer is this likely to be, and what would it likely look like?
Arterial - gravity increases blood flow to the area and alleviates pain.
Arterial - punched out, small lesion. ?Gangrene. Cold with no palpable pulses.
Where do arterial ulcers typically occur?
Toes and heel
Venous vs arterial ulcers:
https://zerotofinals.com/surgery/vascular/legulcers/
How do venous ulcers typically occur?
Secondary to venous insuffiency, superficial trauma and delayed healing.
Accumulation of waste products
Management of arterial ulcers;
Urgent vascular referral
Consideration of surgery to increase blood flow to area
Management of venous ulcers;
4 layer compression bandage
Oral pentoxyphylline is a pripheral vasodilator improves healing rate
MUST exclude arterial ulcer first though using ABPI
Input from specialist nurses, tissue viability etc etc.
Avoid NSAIDs
How is arterial disease excluded when assessing an ulcer?
ABPI
Rhinophyma is a late complication of which skin disorder?
Rosacea
Treatment of predominant erythema in rosacea;
Brimonidine gel - short term relief, lasts for about 6 hours. Alpha adrenergic agonist.
What kind of therapy may be appropriate for individuals with prominent telangiectasia in rosacea?
Laser therapy
What ocular involvement can occur in rosacea?
Blepharitis - inflammation of eyelid margins. Grittiness and discomfort , ?swollen eyelids, ?sticky.
Often due otto mebonium gland dysfunction.
Mild to moderate papules / pustules in rosacea - management?
Topical ivermectin
Severe rosacea combination therapy:
Oral doxycycline and topical ivermectin
Bullous pemphigoid vs pemphigus vulgaris:
Bullous pemphigoid - classically SPARING of the mucous membranes
What are the antibodies directed against in the autoimmune disease pemphigus vulgaris?
Desmoglein 3 - cadherin epithelial cell adhesion molecule
What are the antibodies directed against in the autoimmune disease bullous pemphigoid?
Hemidesmosomal proteins BP180 and BP230
What type of hypersensitivity reaction occurs in pemphigus vulgaris and bullous pemphigoid?
Type II - cell mediated, IgG and M
Give an example of a sedating antihistamine.
Chlorphenamine
The most common cause of urticaria is allergy. Give some drugs that commonly cause urticaria.
I’m itching to play the P(i)ANO
Penicillins
Aspirin
NSAIDs
Opiates
You can get acute and chronic urticaria, usually caused by allergy and autoimmune respectively. What is the pathophysiology of urticaria presentation?
Urticaria is due to the release of histamine from mast cells. Associated with angioedema and flushing.
Chronic urticaria is an autoimmune conditions where autoantibodies target mast cells and trigger them to release histamine and other chemicals. Give 3 sub-categories it can be divided into:
Chronic Idiopathic
Chronic Inducible
Autoimmune - related to autoimmune conditions e.g. SLE.
Chronic inducible urticaria describes episodes of chronic urticaria that can be triggered by e.g. -
Sunlight
Temp change
Exercise
Strong emotions
Hot or cold weather
Pressure (dermatographism)
What is the antihistamine of choice for chronic urticaria?
Fexofenadine
Most common cellulitis organism?
Strep pyogenes
Investigations in cellulitis?
CLINICAL DIAGNOSIS
Bloods and blood cultures only needed if patient is being admitted and septicaemia is suspected.
Which classification is used to grade cellulitis?
ERON classification
I No systemic features or uncontrolled comorbidities
II Systemically unwell, OR systemically well with a comorbidity that could complicate the cellulitis e.g. PAD, obesity.
III Significant systemic upset
IV Sepsis or severe life threatening infection e.g. nec fasc
What constitutes ‘significant systemic upset’ as per the Eron classification of cellulitis (Class III)?
Acute confusion
Deranged obs e.g. tachypnoea, tachycardia, hypotension
Unstable comorbidities
Limb threatening infection due to vascular compromise
Who should be admitted for IV antibiotics with cellulitis?
Eron class III/IV
Severe or rapidly deteriorating
<1 year or very frail
Immunocompromised
Significant lymphoedema
Facial or periorbital
Class II may avoid inpatient care if there are facilities in the community to give IV abx and monitor
First, second and pregnancy treatment for Eron class I cellulitis:
- Oral flucloxacillin
- Oral clarithromycin
Erythromycin in pregnancy
Type I Nec fasc is caused by:
Mixed anaerobe and aerobes, usually post-surgery in diabetics.
Type 2 nec fasc is caused by:
Usually strep pyogenes
The most common pre-existing medical condition in nec fasc is diabetes. Which drug further increases this risk?
SGT2i
Most commonly affected site in nec fasc
Perineum Fournier’s
What is pyoderma gangrenosum?
Rare, non-infectious inflammatory disorder.
Neutrophilic infiltration into the affected tissue.
Where is pyoderma gangrenosum typically found?
Lower leg
Often at the site of minor injury
Most common / defining features of pyoderma gangrenosum:
Painful blisters
Purple edge
Deep necrotic ulcer late stage
?Fever, myalgia
Treatment for pyoderma gangrenosum:
Oral steroids
Causes / associations of pyoderma gangrenosum:
50% idiopathic
IBD 10-15%
RA, SLE
Lymphoma, myeloid leukaemia, myeloproliferative disorders
PBC
GPA
Alopecia areata is presumed to be an autoimmune condition. What is the pattern of hair loss, and prognosis?
Localised, well demarcated patches of hair loss.
Small broken exclamation mark hairs at the edges.
50% regrow by 1 year, and 80-90% eventually.
Potential treatments for alopecia areata:
Topical steroids
Topical minoxidil
Phototherapy
Dithranol
