A 3 year old child has eczematous dermatitis on extensor surfaces. His mother has a history of Bronchial asthma. Diagnosis should be

Atopic dermatitis Eczematous dermatitis on extensor surface and the history of bronchial asthma suggests the diagnosis of Atopic dermatitis. Atopic dermatitis Etiology and pathogenesis Genetic predisposition is very impoant but the precise mode of inheritence is unceain. Atopic diseases tend to run true to type within each family. In some families the affected members predominantly have eczema while in others respiratory problems predominate. This is probably because the dermatitis and asthma are inherited through separate though closely related genetic pathways. Immunological changes Elevated /gE level seen in 80% of the patients. Abnormalities in lymphocytes are also seen. Clinical features Clinical picture varies with the age of the patient (i) Infantile Begins at about 3 months Severely itchy exudative lesions on face and other pas. (ii) Childhood Itch leathery flexural lesions, sometimes extensor lesions occur. (iii) Adult Lichnefied itchy lesions Seen in cubital and popliteal fossa. Seborrhic dermatitis Caused by an yeast, Malassezia futfur Usually seen in adults, sometimes in infants but not in children. The lesions involve the scalp, face (nasolabial folds, eyebrows and eyelashes) presternal and interscapular regions and major flexures (axilla, groin and inframammary region) umbilicus and natal cleft. This distribution of seborrhic dermatitis is very characteristic and is called "seborrhic distribution". Contact dermatitis It develops due to contact with chemicals.