Eczema Flashcards
- eczema can be classified as exogenous/contact or endogenous
- there is confliction about classification of eczema . eczema is sometimes used interchangeabley with dermatitis.*
- types of exogenous (3)
- types of endogenous (7)
- irritant, allergic, (main two) photodermatitis
- subtypes inc - juvenile plantar deramtosis, napkin/diaper dermatitis*
- atopic, seborrhoeic, discoid/nummular, pompholx, gravitational (venous, stasis), asteotic, neurodermatitis
-acute eczema (6)
- ITCH
- erythema
- papules
- weeping and crusting
- blistering
- scaling
- usually illdefined border*
-features of chronic eczema, comparatively (7)
may show all the features of acute, always itch.
- less vesicular
- more scaly
- more pigmented
- more thickened
- more likely to show lichenification
- more likely to fissure
-how to distinguish between allergic contact and irritant contact eczema/dermatitis
patch testing can aid diagnosis of allergic dermatitis
-with allergic dermatitis
> patch testing. use diluted, standardiazed non-irritant allergen . eczema will develop at site of patch after 48-96hr. this can confirm diagnosis. difficulty is chosing correct allergens to test.
-with irritant dermatitis
>patch testing with irritants is of no value
-irritant contact dermatitis
>common causes (5)
>onset.
-irritant contact dermatitis
>can be caused by - detergents, alkalis, solvents, oils, abrasive dusts
>onset- strong irritants cause acute reaction after brief contact and diagnosis is usually obious. week irritants required prolonged exposure even years eg over hands and forearms.
allergic contact dermatitis
- type of reaction. features (4)
- some typesof allergens (7)
- type 4 hypersensitivity
- previous contact is required to induce sensitization, specific to chemical and its close relatives, all areas of skin react, desensitization seldom possible
- metals, cosmetics, preservatives, medications, rubber, plants, resins
allergic contact dermatitis - presentation and clinical features
-allergic contact dermatisis should be suspected if (3)
- certain areas are involved. eg under jewery in nickel allergy.
- -*contact with known allergens
- individuals work carries a risk eg hairdressing, flower shop
- atopic can be used to describe the group - atopic eczema, asthma and hay fever. in which there is exuberant production of which immunoglobulin in response to environmental allergents
- there is a strong genetic component
-IgE
- % of cases have onset before 6 months?
- % before 5 yrs old?
- affects at least what % children?
- % cases clear before early teens?
75
80-90
3
60-70
- morphology and distribution of lesions vary with age.
- infancy. distribution (2) morphology (2)
- childhood. distribution (4). morphology (3)
- adults. distribution -same as childhood but also (3). morphology - same as childhood but also (1)
-infancy
>distribution - face, not specific distribution elsewhere (napkin area often spared) morphology - vesicular, weeping
-childhood
>distribution -flexures of elbow and knee (or sometimes the reserve pattern of extensor apects) writsts, ankles.morphology - excoriated, leathery, dry.
-adults
>distribution-also may involve trunk, face, hands.morphology - may have lichenification.
- clincal features of atopic eczema for diagnosis
- must have (1)
- plus three or more of the following (5)
- may also have (1)
-must have chronically itchy skin or report of rubbing and scratching in infant/child
-plus three or more of the following :
>distrubution - Hx of itchiness in skin creases such as folds of the elbows, behind knees, fronts ankles or around the neck. (or face in under 4yrs)
>distribution - visible flexural eczema . (or on face, outer limbs in under 4yrs)
>atopy - Hx of asthma or hayfever or other atopic diease (or in a first degree relative)
>dry skin generally in past yr
>onset - in first 2 yrs of life
-may also have associated ichthyosis=scaling skin
-exacerbators. exogenous (7). endogenous (2)
-Irritants - soaps, cosmetics
-contact allergens - prick tests may help diagnose
-Inhaled allergens - house dust mites, pollens, pet dander and moulds
-Skin infections - esp Staphylococcus aureus
-Extremes of temperature and humidity
> most patients improve in summer, sweat can exaccerbate
-Abrasive fabrics - wool
- Stress
- Hormonal changes in women - premenstrual , pregnancy.
atopic eczema - complications (5)
-poor sleep in children
-poor growth
> poor sleep can lead to growth hormone deficiency levels rise during sleep and poor growth
>absorption of topical steroids can contribute to poor growth
-hyeractive children
-bacterial infection
-viral infection esp herpes simplex
management. psycho (1). social (2)
psycho
-explanation and reassurance
social
- avoidance of exacerbators - eg no pets, avoid others with active herpes
- disturb itching cycle - bangages, short nails
-bio. topical (4). systemic (4)
bio
-topical steroids. can get impregnated dressings
-topical immunosuppressants. do not have SE of thinning skin as steroids. long term safety data not yet available. reserve for severe treatment resistant cases.
-regular use of bland emollients. can be use as soap substitute.
>those with accociated ichthyosis should use ointments rather than creams.
ointments have a higher concentration of oil, compared to creams.
-phototherapy in persitant cases
-sedative antihistamines for sleep. nb antihistimines not main cause of itching so nonsedative ones may not help
-systemic antibiotics in acute flare ups caused by staph aureus
- cyclosporin. an immunosupressant. in persistant cases.
- Azathioprine. an immunosupressant
