Common Skin Conditions Flashcards
1
Q
What is discoid eczema?
A
Eczema which appears in annular disc-like patches
2
Q
DDx for annular disc-like patches
A
Discoid eczema
Psoriasis
Tinea
3
Q
How is discoid eczema treated?
A
Topical steroids (more potent than typical atopic eczema; e.g. clobetasol, fluocinonide)
4
Q
What is asteatotic eczema?
A
Excessive drying of the skin causing itchiness
5
Q
22 year old student presents with 3/12 of worsening rash not responding to 1% hydrocortisone cream
O/E: erythematous, ill defined, scaly, patches in flexures
Likely Dx?
A
Atopic eczema
6
Q
What are the clinical features of atopic eczema (symptoms, appearance, distribution, exacerbating factors)?
A
Symptoms: itchy ++
Appearance: erythematous, scaly, diffuse, ill defined
Distribution: flexural (thinnest skin)
Exacerbating factors: worse in winter (dry) and summer (heat)
7
Q
What is the atopic triad?
A
Atopic asthma
Allergic rhinitis
Atopic eczema
8
Q
What are the major risk factors for atopic eczema?
A
Genetic predisposition (FHx)
Atopy (asthma, allergic rhinitis)
9
Q
Describe the “model” of atopic eczema
A
Genetic predisposition may include a filaggrin mutation, which leads to reduced barrier function of the skin
This predisposition combined with environmental triggers causes eczema to arise
10
Q
List 6 environmental triggers for atopic eczema
A
Irritants (e.g. soaps)
Allergy
Weather: heat or dry
Infection (e.g. Staph)
“Itch-scratch cycle”
Stress, anxiety
11
Q
What is lichenification and when is it seen?
A
Result of chronic rubbing and scratching
Can be seen with chronic eczema
12
Q
In what patient populations (and what anatomical distribution) is asteatotic eczema seen?
A
Worse on front of legs of elderly patients
13
Q
What factors may exacerbate asteatotic eczema?
A
Seasonal: “winter itch” (heat and drying exacerbates, as for typical eczema)
14
Q
How is asteatotic eczema treated?
A
Topical steroid ointment
Emollients
15
Q
What is pompholyx? Typical location?
A
Vesicular eczema of the hand and foot
16
Q
What factors may precipitate pompholyx?
A
Excessive washing and sweating
17
Q
How is pompholyx treated?
A
Potent topical steroid
Avoidance of detergents, soaps, other irritants
Regular emollients
18
Q
What is diffuse erythrodermic eczema?
A
Severe eczema affecting >90% BSA and associated with significant morbidity
Erythroderma can be caused by pre-existing dermatoses (dermatitis, psoriasis) but may also be the result of internal or haematological malignancy, GVHD or HIV
19
Q
How is diffuse erythrodermic eczema treated?
A
Intense topicals and systemic immunosuppression
20
Q
List 2 complications of eczema
A
Bacterial superinfection
Eczema herpeticum
21
Q
Why is there risk of bacterial superinfection in eczema?
A
Eczematous skin lacks naturally occuring antibacterial peptides
22
Q
Which organism typically infects eczema? How does this appear?
A
Staph aureus
Produces a “golden crust”
23
Q
How is bacterial superinfection treated?
A
Successful treatment requires systemic anti-Staph Abx
24
Q
What is eczema herpeticum?
A
Secondary infection by HSV virus
25
How does eczema herpeticum present?
Sudden onset
Worsening of pre-existing eczema with painful vesicles and "punched out" erosions
26
Why is eczema herpeticum considered a medical emergency?
Risk of corneal scarring
27
How is eczema herpeticum managed?
Needs assessment by opthalmologist
Systemic antiviral treatment
28
What types of contact dermatitis exist?
Irritant
Allergic
29
How is allergic contact dermatitis diagnosed?
Patch testing
30
Describe some typical patterns for allergic contact dermatitis
Streaky dermatitis from plant allergy
"Belt buckle" dermatitis from nickel allergy
Eyelid dermatitis from allergy to formaldehyde in nail polish (don't get rash where skin is thicker, get rash on face where you touch)
31
Describe 3 general measures for treatment of atopic eczema
Avoid soap (use soap substitute, non detergent)
Regular emollient (e.g. sorbolene cream)
Warm (not hot) showers
32
Describe 3 specific measures for treatment of atopic eczema
Topical steroid to inflamed areas (e.g. potent steroid to body)
Mild steroid for face, or non-steroid anti-inflamatory creams (e.g. pimecrolimus)
Treat infection if suspected with systemic Abx
33
What treatment options exist for atopic eczema?
General measures
Specific measures
Wet dressings
Phototherapy with UVB
Systemic immunosuppression
34
What options exist for systemic immunosuppression for treatment of atopic eczema?
Short term: oral pred
Medium to long term: azathioprine, cyclosporin A, methotrexate, mycophenolate mofetil
35
42 year old man, 3 year Hx of worsening rash and significant arthritis in back, hips and knees
O/E: well demarcated plaques, extensor surfaces, very erythematous, scaly +++
Likely Dx?
Chronic plaque psoriasis
36
What are the clinical features of psoriasis (symptoms, appearance, distribution)?
Symptoms: can be itchy, but not as severely as eczema
Appearance: silvery scale +++ , well demarcated, "salmon pink" (very erythematous)
Distribution: extensor rash, symmetrical
37
What is a major risk factor for psoriasis?
Genetic predisposition (FHx in 30% of patients)
38
What is the typical age of onset for psoriasis?
2 peaks: 20s and 50s
39
What symptoms occur alongside scalp psoriasis?
Scalp itch and irritation
Silvery scale ++
40
How is scalp psoriasis managed?
Responds to topical therapy with LPC, salicyclic acid, topical corticosteroids, calcipotriol
41
What other sites (apart from extensor surfaces) can psoriasis occur?
Scalp psoriasis
Periauricular and auricular involvement
Flexural psoriasis (less scaly; "glazed" appearance)
Genital psoriasis (less scaly; "glazed appearance)
Palmar-plantar psoriasis
Nail psoriasis
42
What does guttate "raindrop" psoriasis indicate about a possible underlying cause?
May be triggered by streptococcal infections
43
How does post-streptococcal guttate psoriasis present?
Occurs 1-2 weeks after Streptococcus URTI/tonsillitis
Sudden generalised onset of small plaque psoriasis
44
Describe the typical course of treated post-streptococcal guttate psoriasis
Most clears with treatment but recurs if patient acquires a Strep infection again
45
How is post-streptococcal guttate psoriasis treated?
Very responsive to phototherapy
46
How does generalised pustular psoriasis present?
Acute pustular flare of psoriasis
Often accompanied by systemic Sx (fever, chills)
47
What complications can occur in generalised pustular psoriasis and what is the mechanism of this?
Risk of pre-renal impairment, high output cardiac failure, sepsis
Due to loss of barrier function of the skin, loss of thermoregulation and protein loss
48
What Mx is indicated in generalised pustular psoriasis?
Requires hospital admission to stablise
49
When is there an increased risk of psoriatic arthritis?
If patient has nail psoriasis
50
What % of patients develop psoriatic arthritis?
10%
51
List 5 presentations of psoriatic arthritis
Oligoarthritis
Distal symmetrical polyarthritis
Ankylosing spondylitis
Rheumatoid-like
Arthritis mutilans
52
How is psoriasis treated?
Topical: steroids, tars, calcipotriol, dithranol, keratolytics, emollients
Phototherapy: narrowband UVB treatment, PUVA
Systemic: oral acitretin, methotrexate, cyclosporin, biologic treatments
Often used in combination
53
What is acne?
Disorder of pilosebaceous unit
54
How common is acne?
Affects ~80% of post-pubertal individuals
55
What proportion of cases of acne are classified as moderate to severe?
15-20%
56
What is the typical age of onset for acne?
Teenage disease, but can persist into adulthood
57
Explain the pathophysiology of acne and exacerbating factors
Starts in adolescence with increasing sebum production
Strong genetic component
Can be flared by hormonal factors (menstruation), picking and emotional stress
Can be exacerbated by topic occlusion ("oily" makeup, moisturisers, headwear, hairstyling)
Can be caused by medications (e.g. lithium, anabolic steroids, topical corticosteroids)
58
What are the 4 pathophysiological components of acne?
Abnormal keratinisation of sebaceous duct
Colonisation with bacteria (propionobacterium acnes)
Increase in androgen levels leading to increased sebum production
Inflammation
59
Describe the appearance of acne
Non-inflammatory lesions: open (oxidised sebum) and closed comedones
Mild-moderate inflammatory lesions: papules and pustules
Nodular cystic acne: nodules, cysts, pustules, scarring
Severe cystic acne (acne conglobata)
60
Acne conglobata
Severe cystic acne
61
Describe the temporal profile of adult onset acne in females
Premenstrual flare
62
What is the typical distribution seen in adult onset acne?
Mainly lower face
63
How is adult onset acne treated?
Anti-androgenic OCP +/- anti-androgen
64
When should you consider PCOS in a patient with adult onset acne?
If associated with other signs of androgenisation e.g. hirsutism, androgenetic alopecia
65
What options exist for topical treatment of acne?
Keratolytics
Comedolytic
Anti-bacterial treatments
Combination treatments
66
What keratolytic is used in the management of acne? What is the mechanism of action?
Salicylic acid
Dissolves comedones
67
What comedolytics are used in the management of acne? What is the mechanism of action?
Retinoic acid, adapalene
Dissolves comedones
68
What anti-bacterial treatments are used in the management of acne?
Benzoyl peroxide
Topical erythromycin
Topical clindamycin
69
What combination treatments are used in the management of acne?
Adapalene and benzoyl peroxide
Clindamycin and benzoyl peroxide
70
What systemic treatments are used in the management of acne?
Systemic Abx
Anti-androgenic OCP
Anti-androgens
Systemic retinoids
71
What systemic Abx are used in the management of acne?
Doxycycline 50mg daily
Minoxycline 50mg bd
Erythromycin 400mg bd
Others e.g. trimethoprime 300mg daily
72
What is the rationale of systemic Abx use in the management of acne?
Active against Propionibacterium acnes
Useful against pustular acne
73
What is the limitation of systemic Abx use in the management of acne?
Resistance can develop
Acne recurs on cessation
74
What anti-androgenic OCPs are available for use in acne management?
Ethinyl oestradiol + cyproterone acetate
Ethinyl oestradiol + drosperinone
75
What is the rationale behind use of anti-androgenic OCPs in the treatment of acne?
Reduces sebum secretion
Useful against hormonal acne
76
What anti-androgens are used in the management of acne?
Spironolactone
Cyproterone acetate
77
What is the rationale behind the use of anti-androgens in the management of acne?
Reduces sebum secretion
Very helpful against hormonal acne
Causes menstrual irregularities
78
What systemic retinoids are used in the management of acne?
Isotretinoin
79
What is the rationale behind the use of systemic retinoids in the management of acne?
Comedolytic
Reduces sebaceous gland activity
80
Who can prescribe systemic isotretinoin?
Specialist use only
81
What is the typical duration of a course of systemic isotretinoin?
6-12 months
82
Adverse effects of systemic isotretinoin
Teratogenic ++
Significant mucocutaneous side effects: dryness, photosensitivity (monitoring required)
Controversial association with depression
83
How effective is systemic isotretinoin for the management of severe acne?
60-70% cured after first course
84
What is rosacea?
Common skin disease (1-2% of population) characterised by vascular reactivity and inflammatory rosacea
85
List 4 risk factors for rosacea
Gender (women \> men)
Middle aged
Sun-damaged skin
Celtic
86
What complication of rosacea is exclusive to men?
Tissue hyperplasia (rhinophyma)
87
What clinical features of vascular reactivity and inflammatory rosacea are seen in rosacea patients?
Vascular reactivity: redness, flushing
Inflammatory rosacea: papules, pustules
88
What features are seen in erythrotelangiectatic (vascular) rosacea?
Easy flushing
Background telangiectasia
89
List 7 triggers of vascular reactivity in rosacea
Sunlight
Alcohol
Hot foods and drinks
Spicy foods
Emotion
Heat
Topical steroids may worsen rosacea
90
List 2 long term complications of rosacea
Vascular dilatation (redness, telangiectasia)
Tissue hypertrophy (rhinophyma)
91
How common is ocular rosacea?
Occurs in 20-40% of patients with cutaneous rosacea
92
List 4 symptoms of ocular rosacea
Grittiness
Stinging
Dryness
Itching
93
What signs are seen in mild ocular rosacea?
Watery, bloodshot appearance with interpalpebral conjunctival hyperaemia
94
List 5 general treatments for rosacea
Sun avoidance, SPF 30+ sunblock daily
Avoid spicy foods, EtOH
Avoid topical steroids
Skin care advice: use mild cleansers and bland, non-perfumed moisturisers
Stress management
95
List specific treatments for rosacea and its complications
Vascular rosacea: vascular laser
Inflammatory rosacea: topical metronidazole, topical azaleic acid, systemic Abx (e.g. doxycycline, minocycline), systemic isotretinoin
Rhinophyma: ablative laser or surgery
96
55 year old patient presents with 2/12 Hx of intensely itchy rash
Likely Dx?
Scabies
97
Describe the clinical features of scabies (symptoms, distribution, exacerbating factors, contacts)
Symptoms: intensely itchy rash, often starting on hands, interdigital spaces and feet
Distribution: spreads to genital areas, generalised body rash; spares face and head in adults
Exacerbating factors: itch worse at night
Contacts: often close contacts develop itch after a few weeks (incubation period 4-6 weeks)
98
Describe the rash(es) seen in scabies
Scabies burrows: serpiginous scaly lines, inflammatory scaly papules on hands, feet, interdigital areas, genitals (this is where the mites live!)
Non-specific eczematous rash: secondary hypersensitivity reaction, occurs later
99
How is scabies diagnosed?
Skin scraping of burrow and examination under light microscopy for egg, scabies mite and/or scabies faeces
NOTE: demonstration of mite takes skill, usually treatment is recommended where clinical suspicion is high
100
How is scabies treated?
Treat index case and all close contacts (sexual and household) with 5% permethrin cream applied all over from neck down (especially hands, genitalia and under nails with nailbrush); cream gets left on overnight (8 hrs) and is washed off in the morning (if immunoosuppressed may need oral ivermectin)
Infants \>6 months and children need to treat scalp as well
Clothing needs hot wash and tumble dry (or to be put away for a fortnight for the mites to die)
Index case and all symptomatic cases are retreated after one week
Post-scabetic itch can take weeks to settle
After scabicide treatment, eczema needs to be treated; recommend potent topical steroid with emollients and oral antihistamines
Treat secondary infection if present with Abx
101
How effective is permethrin in treating scabies?
Cure rate \>90% if applied properly
102
What causes the itching in a scabies infection?
Allergy to mite faeces
103
Azathioprine
Purine analogue and systemic immunosuppressant
104
Cyclosporin A
Systemic immunosuppressant (targets T cells)
105
Methotrexate
Anti-folate systemic immunosuppressant
106
Mycophenolate mofetil
Systemic immunosuppressant (inhibits enzyme needed for T and B cell proliferation)
107
LPC
Liquor carbonis detergens (coal tar)
108
Acitretin
Oral retinoid for treatment of psoriasis
109
Azelaic acid
Dicarboxylic acid, used to treat mild to moderate acne
110
111
Calcipotriol
Synthetic derivative of calcitriol, used for chronic plaque psoriasis
