2Eczema : the ward ‘eczema’derived from Greek ekzein,meaning to “to boil forth” or to “effervesce”. it Is a pattern of cutaneous inflammatory response . characterized clinically by : itching , redness , weeping in its acute form and by : dryness , lichenfication in its chronic form.
3and characterized histologically by : 1- lymphocytic infiltrate 2- spongiosis ( intercellular edema ) 3- varying degrees of acanthosis ( increased thickness of epidermal layer ) 4-hyperkeratosis
5Atopic Dermatitis ( Eczema) Atopy: is a genetically determined disorder in which :1-there is increased liability to form IgE antibodies2-there is an increased tendency to have : asthma , hay fever & atopic dermatitisPrevalence :10-20% of the populationare affected .
6Aetiology: 1- Definite aetiology are not well determined 2- AD patients usually have high level of IgE antibodies to ( house dust mites )3- foods clearly exacerbate symptoms in some atopic patients especially children . Eggs , nuts ,cows milk represent 75% of positive food allergies .4- exacerbation also occurs after : immunization , viral infections ,in winter .5- worsening factors : a- cloths irritationb- allergens of airc -excessive washingd- excessive rubbing
7Clinical stages : 1- AD pass into clinicohistological evolution from : acute eczematous eruption in early life tochronic lichenified dermatitis in older patients .2 - AD can be divided into 3 stages ( according to the onset ) :a- infantile AD mo - 2 yrb- childhood AD yr yrc- adolescent and adult onset AD
8Clinical features :* in infancy presented ( mostly after 2 mo. of age )as itchy , erythema of cheeks , in these patches ,fine vesicles develop, rupture and produce moist crusted areas ( i.e. acute moist lesions ).Other sites : scalp, neck, extensor extremities , but diaper area spared .* in childhood AD , usually less exudative , drier , slightly scaly patches involving : eyelids and face , antecubital fossae , popliteal fossae* adult AD : localized erythematous scaly papulovesicular plaques or chronic lichenified plaques, involving same sites of childhood AD .
14Diagnosis :It is based on major and minor criteria and the diagnosis must be :3 majors minorsMajor criteria:1- pruritus2- typical morphology &distribution :a- flexural lichenification in children and adults .b- facial &extensor involvement in infancy .3- chronic or chronically relapsing dermatitis .4- personal or family history of atopic disease ( asthma , alleric rhinitis , atopic dermatitis)
15Minor criteria : 1- xerosis ( dryness ) 2- ichthyosis /hyperlinear palms/ keratosis pilaris3- increased serum IgE4- tendency for cutaneous infection especially (staph.aureus & HSV).5- tendency to non specific hand /foot dermatitis6- chelitis ( inflammation of lips)7- Dennie-Morgan infraorbital folds (> 2 folds )8- orbital darkening9- facial pallor /facial erythema10- pityriasis alba11- perifollicular accentuation12- white dermographism..23-nipple eczema
20Immunopathology of AD: *It is a T-helper type (Th2 dominance ) in tissues.Th2 produce IL4 , 5 ,10*IL4 leads to elevated IgE & oesinophilia in tissues &peripheral blood .* IL10 will inhibit cellular immunitySo , there is tendency towards humeral immunity.* Langerhans cells in skin ( Ag presenting cell in skin ) are abnormal( directly stimulate Th cells without Ag in the way of Th2 phenotype)
21Differential Diagnosis: Infantile AD should be differentiated from seborrhoeic dermatitis in infancybecause of similar presentations .However , it can be differentiated by :Seborrhoeic DermatitisAtopic Dermatitis1- age of onset : before 2 months2- Hx and exam:infant is calmgreasy erythematosequamous lesions involving cheeks , eyebrows , neck, flexures , napkin area , axillae ( i.e. intertriginous areas) .3- Cradle cap on scalp4- normal serum IgE5- prognosis is excellent .1- age of onset : after 2 months2- Hx and exam. :infant is irritable due to itchingweepy erythmatosquamous lesions involving cheeks , extensors (sparing napkin area) .3- Milk Crust over scalp4- increased serum IgE5- prognosis is unpredictable .
22Treatment :1- General measures : avoidance of:- excessive bathing ( or washing ) extremes of cold and heat ,-emotional stress ,-vigorous rubbing .2- Specific measures :A- Topical Rx :* drying agent : e.g. K+ permanganate for weeping lesions.* emollients : for hydration of dry skin e.g. Vaseline ointment and Zinc Oxide ointment .* topical steroids :( moderate to potent ) are very beneficial*topical calcineurin inhibitors :such as tacrolimus or pimecrolimusoffer an alternative to topical steroids.B- Systemic Rx :1- antihistamine : may be used for their sedative effects.2- systemic corticosteroids to control acute and severe cases3- Phtotherapy are often helpful for severe AD( PUVA , NB-UVB )