Skin Rashes Flashcards

1
Q

What is psoriasis?

A

A papule-squamous disorder characterised by red, scaly plaques. The skin becomes inflamed and hyper-proliferates at about 10x the normal rate.

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2
Q

Who gets psoriasis?

A

Age of onset has 2 peaks- 16-22 yr olds and 55-60 yr olds. There is a genetic basis but this is not fully understood.

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3
Q

What is Auspitz’s sign?

A

the appearance of punctate bleeding spots when psoriasis scales are scraped off

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4
Q

Describe chronic plaque psoriasis

A

This is the most common type characterised by well defined, scaly, erythematous plaques usually seen on extensor surfaces. Lesions can be itchy and/or sore.

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5
Q

What is Koebner pneumonon?

A

New plaques occur at sites of skin trauma

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6
Q

Describe flexural psoriasis

A

Usually occurs later in life. There is often less scaling.

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7
Q

Describe guttate psoriasis

A

Raindrop like psoriasis where an explosive eruption of very small circular oval plaques appears over the trunk, usually 2 weeks after strep sore throat.

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8
Q

Describe erythrodermic and pustular psoriasis

A

Most severe types with widespread, intense inflammation of the skin. This can be life threatening.

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9
Q

Describe palmoplantar psoriasis

A

Localised pustular psoriasis confined to hands and feet, no severe systemic symptoms, usually occurs in heavy smokers.

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10
Q

Describe psoriatic nail disease

A

Usually get oncycholysis (nail separates from skin underneath it), nail putting, subungal hyperkeratosis and dystrophy.

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11
Q

Describe the pathology of psoriasis

A

Biopsy will show epidermal acanthosis and parakeratosisi due to increased skin turnover. The granular layer is often absent. Polymorphonuclear abscesses may be seen in the upper epidermis. The epidermal rete ridges appear elongated and clubbed as they fold down into the dermis.

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12
Q

3 complications of psoriasis?

A

Greatly impairs quality of life
Some 5-10% of individuals develop psoriatic arthritis
Psoriasis patients have a higher prevalence of cardio metabolic diseases

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13
Q

When are emollients used in psoriasis?

A

everyone

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14
Q

When are vitamin D analogues used for psoriasis?

A

Localised plaques. Calcipotrol used on extensor surfaces and calcitrol usually used on flexural surfaces. Need to be careful of hypercalcaemia.

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15
Q

When is coal tar used in psoriasis?

A

Anywhere- no limit but usually patients don’t like this treatment

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16
Q

When are steroids used in psoriasis?

A

Usually given in combination as there is a risk of rebound psoriasis

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17
Q

When is phototherapy used in psoriasis?

A

Usually when topical treatments have not worked

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18
Q

Describe systemic treatments for psoriasis

A

Immunosuppression by methotrexate or immune modulation by biological agents

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19
Q

When is dithranol used in psoriasis?

A

In localised plaques if patient complies, it is messy and time consuming, short contact as have to wash off and it stains patients clothes.

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20
Q

Define discoid eczema

A

Well defined probably atopic too. Staph infection is very common in this type of eczema

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21
Q

What is eczema?

A

Itchy, ill-defined, erythematous, scaly rash, lots of types

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22
Q

What is allergic contact dermatitis/ eczema?

A

Immune response to chemicals, topical therapies, nickel, plants etc.

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23
Q

What type of hypersensitivity is allergic contact dermatitis?

A

4

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24
Q

What investigations are done in allergic contact dermatitis?

A

Patch testing to diagnose contact allergy

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25
Q

Management of allergic contact and irritant dermatitis?

A

Avoid allergy or irritant, protective clothing, manage the eczema rash with same as atopic

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26
Q

What is irritant dermatitis?

A

This is not immune mediated and is caused by non-specific irritation. Can be difficult to distinguish from allergic and often the 2 occur together.

27
Q

How is atopic eczema usually distributed?

A

Usually has a flexural distribution (in babies this is different)

28
Q

What factors make someone susceptible to eczema?

A

Other atopic diseases eg asthma, hay fever, food allergy. Associated with filaggrin gene and environmental factors

29
Q

How does eczema look different in skin of colour?

A

Erythema is harder to see, more defined papule and more extensive lichenification

30
Q

What chronic changes can occur in atopic eczema?

A

lichenification (thickening), excoriation (breaks in skin from scratching) and secondary infection (usually Staph A)

31
Q

What is infection of eczema by herpes virus called? How does it present?

A

Eczema herpeticum. High temperature, very painful monomorphic punched-out lesions, systemically unwell child.

32
Q

Treatment of eczema?

A
Plenty of emollients
Avoid irritants including shower gels and soaps
Topical steroids
Treat any infection
Phototherapy- mainly UVB
Systemic immunosuppressants
33
Q

Pathology of eczema?

A

Spongiosis- oedema between keratinocytes

Inflammatory cell infiltrate- acute or chronic lymphocytes and/or neutrophils.

34
Q

Describe photosensitive eczema

A

skin is irritated by sunlight. note the difference in rashes in those taking photosensitive drugs

35
Q

Describe stasis eczema?

A

Caused by hydrostatic pressure, oedema and red cell extravasation making skin easily irritated and damaged

36
Q

Describe seborrhoiec eczema

A

Cradle cap in babies

37
Q

Describe pompholyx eczema

A

Acute form with inflammation

38
Q

Describe lichen simplex eczema

A

excessive scratching of healthy skin causes trauma and eczema

39
Q

What is acne vulgaris?

A

Chronic inflammatory disease of the pilosebaceous unit.

40
Q

Describe pathogenesis of acne vulgaris

A

Lesions arise in the pilosebaceous follicle which becomes blocked due to abnormal keratinisation and increased production of sebum. This leads to overgrowth of propionibacterium acnes which triggers an inflammatory response activation of Toll-like receptors and induction of pro-inflammatory cytokines.

41
Q

Who presents with acne?

A

14-17 yr olds in females. 16-19 yr olds in males. May persist in adulthood.

42
Q

Presentation of acne vulgaris?

A

Occurs in the face and upper torso where the sebaceous glands are very dense. Non- inflammatory features= blackheads (open comedones) or whiteheads (closed comedones). Inflammatory features are papule, pustules, nodules, cysts. Secondary features are scarring.

43
Q

Treatment of acne vulgaris?

A

Avoid oily substances
TOPICAL TREATMENTS
1- benzoyl peroxids (keratolytic and antibacterial)
2- retinoid (drying effect) Tretinoin.
Isotretinoin, Adapalene.
3- topical antibiotic (anti-bacterial and anti inflammatory)
SYSTEMIC TREATMENTS
4- antibiotics usually tetracyclines
5- isotretinoin (oral retinoid loads of side effects)

44
Q

What is rosacea?

A

An inflammatory rash with no comedones

45
Q

Who usually gets rosacea?

A

Mid adult life- the cause is unknown potentially related to the demodex mite

46
Q

Presentation of rosacea

A

rash on nose, chin, cheeks and forehead
Prominent facial flushing exacerbated by sudden change in temperature, alcohol or spicy food.
May get enlarged nose

47
Q

Treatment of rosacea?

A

Reduce aggravating factors, avoid steroids.
Topical metronidazole, ivermectin
Oral tetracycline long term, low dose isotretinoin if severe
For telangiectasia use vascular lazer
For rhinopehyma surgery or laser shaving

48
Q

What are bullous disorders? Give two examples

A

Blistering. Auto-immune diseases where damage to adhesion mechanisms in the skin results in blistering at various levels.

49
Q

Describe four differences between bullous pemphigoid and pemhigus vulgaris

A
Bullous pemphigoid
Large tense bullae
Nikolsky sign negative
Mucosal lesions unlikely
Sub epidermal blister with no evidence of acantholysis

Pemphigus Vulgaris
Thin vesicles that usually rupture to leave raw areas
Nikolsky sign positive
Mucosal involvement is very common
Intra epidermal blister with acantholysis (loss of desmosomes so keratinocytes float away from each other)

50
Q

What is Nikolskys sign?

A

This is when the top layer of skin slips away from lower layers when rubbed.

51
Q

Pemphigoid or pemphigus has a high mortality if left untreated?

A

Pemphigus has high mortality if left untreated. Pemphigoid has much lower risk.

52
Q

How do you investigate pemphigoid and pemphigus?

A

Skin biopsy with direct immunofluorescence and indirect immunofluorescence

53
Q

Treatment of pemphigoid and pemphigus

A

Treat with systemic steroids and other immune-suppressive agents. In pemphigoid you can use tetracyclines. Topical treatments such as emollients, topical steroids, topical anti-sepsis and hygiene measures

54
Q

What is lichen planus?

A

T cell mediated inflammation targeting an unknown protein within the skin and mucosal keratinocytes.

55
Q

Who gets lichen planus?

A

Occurs in middle age

56
Q

Presentation of lichen planus?

A

Rash consisting of intensely pruritic, purple-pink, polygonal papule. Typically effects volar wrists/ forearms, shins and ankles. Wickham’s striae. Mucosal and mucosal genital involvement is common.

57
Q

What are wickham’s striae?

A

Whitish lines visible in the papule of lichen planus

58
Q

Pathology of lichen planus?

A

Lichenoid disorders are characterised by damage to the basement epidermis. Irregular sawtooth acanthuses, hypergranulosis, orthohyperkeratosis. Bandlike upper dermal infiltrate of lymphocytes. Basal damage with formation of cytoid bodies.

59
Q

Histologically what are lichenoid disorders characterised by?

A

Damage to the basement epidermis

60
Q

How long does lichen planus usually last for?

A

12-18 months before burning out (however quite distressing so usually give treatment)

61
Q

Treatment of lichen planus?

A

Check for possible drug precipitant, emollients, topical steroids or oral if extensive. UVB phototherapy or PUVA.

62
Q

What is first line treatment of rosacea?

A

Topical metronidazole gel (if that doesn’t work move onto oral tetracycline)

63
Q

What may person presenting with bullous pemphigoid have months history of preceding the blistering rash?

A

Itch

64
Q

Describe dermatitis artefacta

A

Dermatitis artefacta is a condition in which skin lesions are solely produced or inflicted by the patient’s own actions. This usually occurs as a result or manifestation of a psychological problem. It could be a form of emotional release in situations of distress or part of an attention seeking behaviour. Variable and bizzare histology.