2 year old with a rash on extensor surface, diagnosis-
Ans. is 'b' i.e., Atopic dermatitisAtopic dermatitiso It is a pruritic disease of unknown origin. Usually starts in infancy, through adolescent and adult pattern is also there. There is a clear genetic predisposition. One of the very imp features of this disease is the presence of personal or family history of other atopic conditions. As with other atopic conditions, IgE is raised in atopic dermatitis.Atopic conditions associated with atopic dermatitisAsthmaFood allergyAllergic rhinitisHay feverUrticaria (contact)Allergic conjunctivitisClinical featureso Atopic dermatitis is an itchy, chronic, fluctuating disease that is slightly more common in boys than girls. The age of onset is between 2 and 6 months in the majority of cases, but it may start at any age, even before the age of 2 months in some cases.The clinical features include :ItchingMacular erythema, papules or papulovesiclesEczematous areas with crusting.Lichenification and excoriationDryness of the skinSecondary infection.Increased tendency of vasoconstriction:-Pallor on skin esp cheeks i.e. perioral pallorRunning a blunt object on affected skin produces a white line i.e. white dermatographismAssociated conditions:Alopecia aerataIncrease susceptibility1 to insect bite and stingsAntenna sign - follicular plugging with homy plugsHeadlight sign - cheilitis i.e. inflammation of the skin on around lipsHertoghe's sign - thinning of lateral half of eyebrowsDiagnostic criteria f Hanifin and Raika)Based mainly on clinical experienceMajor criteriaThe family history of atopyChronicityPruritusTypical morphology and distributionMinor criteriaDry skinChelitisElevated edgeDennie's line/Dennie morgan fold (infraorbital fold)White dermographismPeripheral eosinophiliaImmediate (type i) hypersensitivityFacial pallor, orbital darkeningFood intoleranceConjunctivitis (recurrent), keratoconus, cataractPityriasis albaHand dermatitisRecurrent infectionso At least 3 major or 2 major plus 2 minor criteria are necessary for diagnosis.Patterns of Atopic dermatitisInfantile phaseo The lesions most frequently start on the face. Often, the napkin area is relatively spared. When the child begins to crawl, the exposed surfaces, especially the extensor aspect of the knees, are most involved,o The lesions consist of erythema and discrete or confluent oedematous papules,o The papules are intensely itchy. Secondary infection and lymphadenopathy are common.Childhood phaseo From 18 to 24 months onwards, the sites most characteristically involved are the elbow and knee flexures, sides of the neck, wrists, and ankles. The sides of the neck may show a striking reticulate pigmentation, sometimes referred to as 'atopic dirty neck'.o The erythematous and oedematous papules tend to be replaced by lichenification.Adult phaseo Lichenifieation, especially of the flexures and hands, is the main feature. Involvement of the vermilion of the lips and the adjacent skin is common,o Photosensitivity is not uncommon.
Infantile eczema
Atopic dermatitis
Contact dermatitis
viral exanthem