Dermatitis Flashcards
To remember that this is eczema
What is dermatitis?
- Also known as eczema
* A group of inflammatory skin disorders
What are the classifications of dermatitis?
○ Endogenous
- Atopic eczema
- Seborrhoeic eczema
- Discoid eczema
- Chronic hand/ foot eczema
- Venous ("gravitational") eczema
- Asteatotic eczema
- Lichen simplex/ nodular prurigo
○ Exogenous
- Irritant contact eczema
- Allergic contact eczemaDescribe the inflammation in dermatitis
○ Erythema and surface change (dryness and scaling)
○ Itch which may be intolerable (ranges from mild to intolerable)
Describe acute dermatitis
○ Tiny vesicles or larger bullae
○ Oedematous inflamed skin
○ Scratching leads to serosanguinous exudate and crust
Describe subacute dermatitis
○ Less oedema
○ Some flaking and scaling
Describe chronic dermatitis
○ Thickened and dry
○ Prominent skin creases (lichenification)
What happens if a secondary bacterial infection occurs?
○ Crusts
○ Papules
○ Pustules
Describe the histology of dermatitis
○ Acute: Keratinocytes are swollen with increased intracellular fluid
○ Chronic: little oedema but prominent thickening of the epidermis (acanthosis) and scaling (hyperkeratosis)
○ All: Inflammatory cells present around the upper dermal vessels
Explain atopic eczema (briefly)
- Usually starts under the age of 2
- Often associated with other atopic diseases
- Genetically complex familial disease with strong maternal influence
Explain the pathophysiology of atopic eczema
○ Not exactly known
○ Abnormalities in skin barrier function
○ Abnormalities in adaptive and innate immunity
○ Loss of function mutations in the epidermal barrier protein Filaggrin cause ichthyosis vulgaris
○ Filaggrin deficiency
- Poor barrier function
- Dry skin
- Allows antigen penetration into epidermis
What are the exacerbating factors of atopic eczema?
○ Infection (in the skin or systemically)
○ Lack of infection (in infancy) may cause the immune system to follow the T2 pathway and allow eczema to develop
○ Soap, bubble bath and woollen fabric can irritate the skin
○ Teething in young children
○ Severe anxiety or stress can in some individuals
○ Cat and dog dander
○ Delayed food hypersensitivity
What are the clinical features of atopic eczema?
○ Itchy, erythematous, scaly skin patches, especially in flexures of ankles, knees, elbows and wrists and around the neck
○ Infants: eczema starts on cheeks before spreading around the body
○ Very acute lesions: weep or exudate and can show small vesicles
What are the associated features of atopic eczema?
○ Skin of upper arms and thighs may feel roughened due to follicular hyperkeratosis
○ Palms may show very prominent skin creases
○ Dry fish-like scaling of the skin, which is non-inflammatory and often prominent on the lower legs
What are the complications of atopic eczema?
○ Broken skin can become secondarily infected by bacteria
○ Cutaneous viral infections may be more widespread
○ Ocular complications
- Conjunctival irritations
- Keratoconjunctivitis
- Cataracts
What are the investigations for atopic eczema?
○ History
○ Clinical features
What is the prognosis of atopic eczema?
Most will spontaneously clear
What is the management of atopic eczema?
○ Avoid irritants ○ Manipulating diet ○ Topical therapies - Steroids - Calcineurin inhibitors ○ Antibiotics - Flucloxacillin (550 mg 4 times a day) ○ Sedating antihistamines ○ Bandaging ○ Second line agents - UV phototherapy - Ciclosporin - Azathioprine - Methotrexate - Oral prednisolone ○ New drugs - Anti-IL-4/IL-13 monoclonal antibody dupilumab - Omalizumab
What are the clinical features of seborrhoeic eczema?
○ Occurs in greasy areas of the body
○ On the face: scaling and erythema around the nose, medial eyebrows, hairline and ear canals
○ Scalp: dandruff (mild), more severe can look like psoriasis
○ Pre-sternal area in men
○ Large flexures
○ Ano-genital area
○ Self-limiting infantile form: scalp scaling/ crackle cap and a non-itchy napkin dermatitis
What is the management for seborrhoeic eczema?
○ Usually runs a chronic course with relapses
○ Treatment is suppressive rather than curative
○ Topical azole antifungal creams
○ Short term use of mild-moderate potency steroids
○ Topical calcineurin inhibitors (TCIs)
○ Ketoconazole shampoo
Explain venous eczema
• Usually affects the elderly and those with varicose veins or a history of venous thrombosis
• Inner calf is involved
• Coexists with signs of venous hypertension
○ Hemosiderin deposition
○ Lipodermatosclerosis
○ Varicose ulceration
• May be complicated by allergic contact dermatitis
What is the management of venous eczema?
○ Bland emollients
- Liquid paraffin and soft white paraffin mix
○ Short term use of a mildly potent topical steroid
○ Manage underlying venous hypertension
Explain discoid eczema
- Well dermatated, inflamed, scaly patches, sometimes with tiny vesicles
- Usually affects limbs and torso
- Immensely itchy
- Potent topical steroid usually required to clear individual lesions
Explain hand eczema
• Causes
○ Contact dermatitis/ eczema: due to external harsh substance or allergy provoking substance
○ Endogenous dermatitis/ eczema: no external factors can be identified (there may also be involvement of the feet)
• Clinical features
○ In the finger webs and backs of hands
○ Dry, sore chapped skin
○ Extremely common in cold dry weather and those who wash their hands frequently
• Can be part of atopic eczema
• Hyperkeratotic form
○ Dry scaly plaques and cracks on the palms and soles
• Patch testing should be used on anyone with chronic hand eczema to investigate contact allergies
Explain allergic contact and irritant contact eczema
• Delayed type hypersensitivity reaction
• Rash does not appear until 12-24 hour after skin contact
• Management
○ Minimising contact with allergens
○ Managing eczema actively
○ The oral retinoid, alitretinoin
Explain lichen simplex
• Chronic form of eczema
• Skin is thickened and lined in response to repeated rubbing or scratching
• Management
○ Topical antipruritics
○ Short term treatment with a potent topical steroid
○ Advice about habit reversal
Explain nodular purigo
• Very persistent
• Itchy, nodular eruption
• Perpetuated by picking and scratching
• May develop on background atopic eczema
• Scattered, eroded and hyperkeratotic nodules are typically found on the upper trunk and the extensor surfaces of limbs
• Management (only gives temporarily relief)
○ Topical steroids
○ Sedating antihistamines
○ Antipruritics
• Diagnosis
○ Exclusion of other pathologies
