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Dermatology week 2 > Eczema/dermatitis > Flashcards

Eczema/dermatitis Flashcards

1
Q

What is dermaitis ?

A
  • This refers to a group of itchy inflammatory skin conditions characterised variably by erythema, oedema, vesiculation (small fluid-filled blisters), scaling, fissuring & lichenification (thickening of skin)
  • The terms dermatitis & eczema are used interchangably
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2
Q

Describe the histology of dermatitis/eczema in general

A

There is spongiosis with varying degrees of acantholysis & a superficial perivascular lympho-histocytic infiltrate

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3
Q

What are the different classifications of inflammatory dermatitis/eczema based on time ?

A
  • Acute dermatitis/eczema = rapidly evolving red rash which may be blistered & swollen
  • Chronic dermatitis/eczema = referring to a longstanding irritable area. It is often darker than the surrounding skin, thickened (lichenification) & scratched
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4
Q

What are the 2 main classifications of dermatitis/eczema ?

A
  1. Endogenous = mediated by inflammatory processes within or produced by the body
  2. Exogenous = mediated by inflammatory processes originating from causes outside the body
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5
Q

What are the main forms of endogenous eczema ?

A
  • Atopic dermatitis
  • Sebhorroeic dermatitis
  • Discoid eczema (nummular dermatitis)
  • Nodular purigo
  • Lichen simplex chronicus
  • Others
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6
Q

What are the main types of exogenous dermatitis/eczema ?

A
  1. Irritant contact dermatitis
  2. Allergic contact dermatitis
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7
Q

What is sebhorreic dermatitis ?

A

It is a chronic form of eczema/dermatitis that mainly affects the sebaceous gland rich regions of the scalp, face & trunk

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8
Q

What causes sebhorreic dermatitis ?

A

It is thought to be caused by an inflammatory reaction related to proliferation of a skin commensal called Malassezia furfur

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9
Q

What are the 2 forms of sebhorreic dermatitis ?

A
  1. Infatile (babies < 3months)
  2. Adult (tends to begin in late adolescence or the elderly)
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10
Q

What conditions is sebhorreic dermatitis in adults associated with ?

A
  • HIV - if severe or widespread
  • Parkinsons disease
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11
Q

Describe the distribution of infantile sebhorroeic dermatitis

A
  • Commonly on the scalp as ‘cradle cap’
  • Also face, neck, nappy area & limb flexures
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12
Q

What are the clinical features of sebhorreic dermatitis

A

Scalp:

  • ‘Cradle cap’ = erythematous rash with scales which are yellow-brown & greasy

Elsewhere:

  • well-defined areas of erythema ‘salmon-pink’ & scaling (smaller & whiter)

In infantile dermatitis the patient is usually well & itching is relatively mild/negligable

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13
Q

Describe the distribution of adult sebhorroeic dermatitis

A

Mainly affects the scalp, face (esp periorbital, nasolabial & auricular areas) & upper trunk

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14
Q

What are the clinical features of adult sebhorroeic dermatitis ?

A
  • Well-defined patches of erythema with scaling & flaking of the skin
  • Scales may be white/yellow or oily/dry
  • Mild itch
  • Scalp lesions may cause dandruff
  • Ottitis externa & blepharitis may develop
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15
Q

How is sebhorroeic dermatitis diagnosed ?

A

Clinically

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16
Q

What is the treatment of infantile sebhorroeic dermatitis ?

A

For scalp:

  • 1st line = topical emollient (e.g. olive/veg oil) & brush gently & wash with baby shampoo
  • 2nd line = topical imidazole cream (clotrimazole 1% or miconazole)

Elsewhere:

  • 1st line = bathing using emollient + barrier emollent (e.g. zinc & caster oil or parrafin ointments) + consider topical imidazole (clotrimazole 1% or miconazole)
  • If nappy rash develops consider low potency TCS (hydrocortisone 1%)
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17
Q

What is the treatment of adult sebhorroeic dermatitis on the scalp & beard ?

A
  • 1st line = ketonazole 2% shampoo or selenium sulphide shampoo
  • 2nd line = other medicated shampoo e.g. zinc, pyrithione, coal tar, or salicylic acid

Adjunct if severe itch then add short course of TCS e.g. betatheasone valivate 0.1% or mometasone furate 0.1%

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18
Q

What is the treatment of adult sebhorroeic dermatitis on the face & body ?

A

1st line = topical anti-fungals - ketonazole 2% cream or imidazole (clotrimazole 1% or miconazole) + midly potent TCS (hydrocortisone 0.5% or 1%)

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19
Q

What condition may patients with sebhorroeic dermatitis develop later in life ?

A

Psoriasis or atopic eczema

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20
Q

What is discoid (nummular) eczema/dermatitis ?

A

An endogenous type of eczema/dermatitis in which there are scattered, roundish plaques or eczema

Note - usually plaques are less well-defined and have a finer more powdery scale than psoriasis

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21
Q

Who most commonly gets discoid eczema ?

A
  • Can affect children & adults
  • In males > 50 it is associated with chronic alcoholism
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22
Q

Describe the typical distribution of discoid eczema

A

Usually affects the limbs esp the legs. However, may affect trunk

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23
Q

What are the clinical features of discoid eczema ?

A
  • Well-circumscribed round or oval plaques which are inflammed
  • Very itchy
  • May be 1. eudative = oozy papules, blisters & plaques or 2. dry = erythematous, dry plaques
  • Plaques can be clear in centre ==> resembling ringworm
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24
Q

How is discoid eczema diagnosed/investigated?

A
  • Diagnosed clinically
  • But, skin scrappings doen to rule out tinea corporis (ringworm)

Pic shows discoid eczema presenting similar to ringworm

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25
Q

How is discoid eczema treated ?

A

Emollients + TCS (mild)

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26
Q

What is nodular prurigo?

A
  • It is a skin condition characterised by very itchy firm lumps.
  • It is the most severe form of prurigo (prurigo refers to intensley itchy spots)
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27
Q

What is the cause of nodular prurigo?

A

The cause if unknown. It is uncertain whether scratching leads to the nodules or if the nodules appear beforre they are scratched

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28
Q

Who is nodular prurigo most common in ?

A
  • 80% of patients are atopic i.e. have asthma, eczema, hayfever or other allergic conditions
  • In some it may start following an insect bite
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29
Q

Describe the typical distribution of nodular prurigo

A

The lateral aspects of the arms & legs are most commonly affected

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30
Q

What are the clinical features of nodular prurigo ?

A
  • An individual nodule is a firm lump 1-3cm in diameter
  • Nodule has a thick surface & may have a scab, crust or scratch marks on top of it
  • Nodules are intensley itchy
  • Nodules are grouped & numerous
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31
Q

How is nodular prurigo diagnosed?

A

Clinically, but if doubt do skin biopsy to confirm

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32
Q

How is nodular prurigo treated ?

A
  • 1st line = emollients + ultrapotent TCS (applied under occlusion e.g. plastic cover) + oral anti-histamine e.f. fexofenadine or certirizine + phototherapy
  • 2nd line = immuno-suppressive treatments - oral steroids, ciclosporin, methotrexate or azathioprine
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33
Q

What is lichen simplex ?

A
  • This is a localised area of chronic, lichenified (thickened/leathery) eczema/dermatitis
  • There may be single or multiple plaques
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34
Q

What is the cause of lichen simplex?

A

It results from repetative scratching & rubbing, which arises because of chronic localised itch. The primary itch can be due to:

  • Atopic eczema
  • Contact dermatitis
  • Venous eczema
  • Psoriasis
  • Lichen planus
  • Fungal infection
  • Insect bites
  • Neuropathy
35
Q

Who most commonly gets lichen simplex ?

A
  • Usually occurs in adults
  • More common in people with anxiety &/or OCD
36
Q

Describe the distribution of lichen simplex

A
  • It is often solitary & unilateral (multiple plaques can arise)
  • Most often affecting the back of scalp & neck, scrotum or vulva, wrist & forearms, lower legs
37
Q

What are the clinical features of lichen simplex ?

A

A solitary plaque of lichen simplex is circumscribed, linear or oval in shape & markedly thickened.

Other features include:

  • Exaggerated skin markings
  • Dry or scaly surface
  • Leathery induration (hardening)
  • Broken-off hairs
  • Pigmentation
  • Scratch marks
38
Q

How is lichen simplex diagnosed ?

A

Usually clinically.

39
Q

What is the treatment of lichen simplex?

A

Potent TCS ointment e.g. bethamethasone + a midly anxiolytic anti-histamine e.g. hydroxyzine to help with sleep as itch can be so severe to distrub sleep

+ emollient

40
Q

What is irritant contact dermatitis ?

A

It is a form of contact dermatitis which is a non-immunological inflammatory reaction caused by the direct physical or toxic effects of an irritating substance on the skin

41
Q

List the common irritants which cause irritant contact dermatitis

A
  • Water esp repeated or prolonged contact
  • Sweating under occulsion
  • Detergents, soaps & cleaning agents
  • Solvents & abrasives
  • Machine & cutting oils
  • Acids & alkalis
  • Reducing & oxidising agents
  • Powders, dust & soil
42
Q

Who most commonly gets irritant contact dermatitis ?

A

Anyone can get it but those with atopic dermatitis are particularly susceptible

43
Q

Describe the distribution of irritant contact dermatitis

A

Usually confined to the site of contact with the irritant

44
Q

What are the clinical features of irritant contact dermatitis ?

A

Exposure to strong irritants such as strong acids or alkalis can cause immediate reactions whereas mild irritants usually produce reactionns over a prolonged or repeated exposure:

  • Well-demarcated red patch with a glazed surface, there may be swelling, blistering & scaling of the damaged area
  • Vesicles less commonly seen than in allergic contact dermatitis
  • Mild irritants e.g. water may over weeks cause more dryness, itching & cracking of the skin, eventually sores appear & form crusts/scales
  • Symptoms of stinging, burnign, dryness & tightness may be felt
45
Q

List some of the typical examples of irritant contact dermatitis

A
  • Dribble rash around the mouth or chin in a baby due to lip-licking in children
  • Napkin dermatitis (diaper rash) due to urine & faeces
  • Chemical burns
  • Housewife eczema
  • Underneath a ring due to accumulation of soaps, detergents & creams
  • Cosmetics
  • Gloves
  • Fibreglass
  • Dry cold air
46
Q

How is irritant contact dermatitis diagnosed ?

A
  • No specific test.
  • Note a pos patch test does not exclude irritant as allergic & irritant contact dermatitis may co-exist
47
Q

What is the treatment of irritant contact dermatitis ?

A
  • Avoidance of irritant is key
  • Emollient + TCS
  • Chemical burns should flushed with water + antidote/remedy
48
Q

What is allergic contact dermatitis ?

A

It is a type IV (delayed) hypersensitivity reaction that occurs after sensitiation & subsequent re-exposure to a specific allergen or allergens

49
Q

List the common allergens which cause allergic contact dermatitis

A
  • Personel care products esp skin care, nail varnishes, fragrances, sun-screen & hair dye
  • Metals such as nickel & cobalt (often jewellerry), chromate (found in cement)
  • Topical medications e.g. anti-infective agents & TCS
  • Rubber addicitves (in footwear, gloves etc)
  • Plants
  • Adhesive plasters
50
Q

Who is most commonly affected by allergic contact dermatitis ?

A
  • Women due to jewellery & comsmetic use
  • Older people due to topical antibiotics
  • Also metal workers, hairdressers, beauticians, healthcare workers, painters & florists
51
Q

Describe the typical distribution of allergic contact dermatitis

A

Usually confined to the site of contact

52
Q

What are the clinical features of allergic contact dermatitis ?

A
  • Occurs some hrs after contact with allergen
  • Typically presents with erythema & vesiculation
  • Dryness, scaling & bullae may also be present
53
Q

How is allergic contact dermatitis diagnosed?

A

Patch testing is gold standard

54
Q

What is the treatment of allergic contact dermatitis ?

A

Avoidance of allergen is key

Treat active dermatitis with Emollients + TCS

55
Q

What is atopic dermatitis/eczema ?

A

It is a chronic, itchy, inflammatory skin condition that affects people of all ages although it presents most frequently in childhood

56
Q

In who does dermatitis/eczema classically develop in?

A

In people with ‘atopic tendancy’ meaning it typically develop in people with any or all of the different atopic conditions

Atopic conditions are:

  1. Eczema
  2. Asthma
  3. Hay-fever
  4. Food allergy
57
Q

What is meant by the term ‘atopic march’?

A
58
Q

What is atopic dermatitis caused by ?

A
  • There is no known single cause. It is a complex condition involving genetic, immunological & environmental factors leading to a dysfunctional skin barrier & immune system dysregulation
  • Mutations in filaggrin gene is likely the cause for almost 50% of cases
59
Q

What is the function of the skin barrier & the main component of this barrier ?

A

The cornified cell envelope (CCE) is the main outer cutaneous barrier

Functions:

  1. Prevents water loss
  2. Prevents entry of infectious agents, irritants & allergens

Impairment of these functions is a major cause of atopic eczema

60
Q

What is the importance of the filaggrin gene and what 2 conditions is mutation of it linked to ?

A
  • It is essential for the conversion of keratinocytes to the protein/lipid squmes that make up the outermost barrier layer of the skin. A defect in filaggrin results in a dysfunctional skin barrier
  • Mutation is linked to development of ichthyosis vulgaris & atopic dermatitis
61
Q

List some of the possible environmental triggers which can result/contribute to the development of atopic dermatitis/eczema

A
  • Soap & detergent
  • Animal dander
  • House dust mites
  • Extreme temps (hot/cold)
  • Rough clothing
  • Pollen
  • Foods (esp in infants)
  • Stress
  • Infection
  • Xerosis (dryness)
62
Q

In what parts of the world is atopic dermatitis eczema more common in & why is this thought to be so ?

A
  • Higher prevelence in westernised/ industrialised countries.
  • Possibly due to hygeine hypothesis of less viral infection in these areas, increased washing etc
63
Q

What is ichythosis vulgaris ?

A
  • The most common form of ingerited ichythosis (‘fish-scale skin diseases) charactrised by excessive dry, scaly skin.
  • It is usually an inherited condition but can be aquired
64
Q

What causes ichythosis vulgaris ?

A

Mutation of the gene encoding filaggrin (FLG)

65
Q

What are the clinical features of ichythosis vulgaris ?

A
  • Dry scaly skin (xerosis) affecting the extensor aspects of the limbs, scalp, face & trunk
  • Skin folds usually spared
  • Associated with keratosis pilaris (dry skin, hair follicles plugged by scale think your arms ruaridh) & hyperlinearity (pronounced skin line) of the palsm & soles
66
Q

In infants with atopic eczema what allergy do they commonly have & how is it diagnosed?

A
  • Food allergy most commonly egg & milk. This usually resolves as they get older.
  • Diagnosis = specific IgE levels on skin prick testing

Note - history suggestive of this would be an infant with worsening eczema +/- type I hypersensitivity reactions &/or GI symptoms

67
Q

Describe the typical distribution of atopic eczema

A
  • In infants the face & trunk often affected
  • In younger children often extensor surfaces affected
  • In older children it typically affects flexor surfaces & the creases of the face & neck (think chris)
68
Q

What are the clinical features of atopic dermatitis ?

A
  • Cardinal symptom is itch!
  • Ill-defined erythema & scaling
  • Generalised dry skin
  • Acute flares - may become inflammed, red, blistering & weaping
  • Chronic changes due to itching - lichenification, scarring, pigmentation changes, habit scratching (chris), infection
69
Q

How is atopic eczema diagnosed?

A

Clinically

70
Q

What are the NICE criteria used to help diagnose atopic eczema ?

A

Itching + ≥ 3 of:

  • Visible flexural eczema
  • History of flexural eczema/rash
  • Personal history of atopy
  • Dry skin in past year
  • Onset of signs & symptoms before age of 2 y/o
71
Q

What problem can eczema result in ?

A

Itching ==> lack of sleep ===> irritability, mood change, lack of concentration, schooling problems

72
Q

How is the severity of atopic eczema assessed?

A
  • Clear — if there is normal skin and no evidence of active eczema.
  • Mild — if there are areas of dry skin, and infrequent itching (with or without small areas of redness).
  • Moderate — if there are areas of dry skin, frequent itching, and redness (with or without excoriation and localized skin thickening)
  • Severe — if there are widespread areas of dry skin, incessant itching, and redness (with or without excoriation, extensive skin thickening, bleeding, oozing, cracking, and alteration of pigmentation)
  • Infected — if eczema is weeping, crusted, or there are pustules, with fever or malaise.
73
Q

What is the treatment of atopic eczema ?

A
  • For simply dry skin tx = emollients alone
  • For mild atopic eczema tx = emollients + mild TCS
  • For moderate atopic eczema tx = emollients + moderate TCS (calcineurin inhibitor may be used)
  • For severe atopic eczema tx = emollients + potent/very potent TCS
74
Q

What adjuvant treatments may be added to treat symptoms of atopic eczema?

A
  • If severe itch or urticaria tx = non-sedating anti-histmaine (certirizine, loratidine or fexofendadine)
  • If severe itch affecting sleep tx = sedating anti-histamine e.g. chlorphenamine
  • Occulsive dressings or dry bandages may be of benefit
  • For steroid sparing tx options in severe eczema = Phototherapy or systemic immunosuppressants (azathioprine, methotrexate, mycophenolate mofetil, ciclosporin)
75
Q

When is the use of anti-histamines contraindicated in the treatment of atopic eczema ?

A

if < 6 months old

76
Q

What is the 2nd line option which can be used instead of TCS’s when wanting to reduce the effects of steroids in a patient with atopic eczema ?

A

Topical calcineurin inhibitors (tacrolimus or pimecrolimus (face only))

77
Q

What are the different strengths of TCS ?

A
78
Q

What quantity of TCS is needed when applying it ?

A
  • 1 finger tip unit = 1/2g which covers 2 hands area
  • 1 application to whole body = 20-30g ointment
79
Q

What are the main SE’s of steroids ?

A
  • Skin thinning
  • Increased skin infections
  • Telangectasia & steroid acne
  • Poor growth
  • Cushinoid features
  • Striae
80
Q

What emollients should be used in the treatment of eczema ?

A
  • Greasy ointments for dry scaly, fissured or lichenified skin
  • Thinner creams for hot, inflammed urticated skin
  • Regular bath/shower emollients should be used
81
Q

What infectious complications of atopic eczema can arise ?

A

Bacterial infection - usually caused by staph.A or sometimes strep.pyogenes. May present as typically impetigo or as a worsening of eczema

82
Q

What is pompholx and what are the signs/symptoms ?

A

It is a type of eczema which affects the hands (+fingers) and sometimes the feet

Signs/symptoms:

  1. Skin is initially very itchy with a burning sensation of heat and prickling in the palms and/or soles.
  2. Then comes a sudden crop of small blisters (vesicles), which turn into bigger weepy blisters, which can become infected, causing redness, pain, swelling, and pustules.
  3. There is often subsequent peeling as the skin dries out, and then the skin can become red and dry with painful cracks (skin fissures).
83
Q

What is shown in this pic ?

A

The subsequent peeling of skin seen in pompholx

Dermatology week 2 (22 decks)

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