Early Clinical Differential Diagnosis Between Infant Atopic Dermatitis and Seborrheic Eczema

Background: Clinical differential diagnosis between atopic dermatitis and seborrheic eczema is sometimes difficult. Early differential diagnosis is important, since atopic dermatitis can be more difficult to treat and may be associated with asthma and allergic rhinitis.

Methods: In a cohort study, 96 infants with high risk for atopic dermatitis were followed up from the maternal ward until they completed one year of age. The infants were submitted to complete skin examination, monthly, for a 1 year period. A full skin examination was performed and any sign of eczema was registered. Therapy with hydrocortisone 1% cream was prescribed. Eczema onset time, skin distribution, response to therapy and the presence of pruritus were evaluated.

Results: 87 (96%) infants fulfilled the study criteria (physical examination at least 10 months). 54 (62%) infants had signs of eczema during one year follow up. Atopic dermatitis was diagnosed in 14 (16%) patients and seborrheic eczema in 30 (34,5%) infants, with 10 (11,5%) classified as: both eczemas. Atopic eczema onset was mainly between 2 and 4 months and seborrheic eczema between 1 week and 3 months, with an important coincident period. Facial eczema had similar onset and semiological aspect for both diseases in its beginning. Head eczema was present in 40 (74%) eczema infants, 33 (82,5%) with a posterior diagnosis of seborrheic eczema and 7 (17,5%) with atopic dermatitis. After 3 to 5 months, axillar and groin folds eczema were the main signs of seborrheic dermatitis diagnosis, while face, neck and limbs were the main eczema sites in atopic dermatitis. The 10  infants with dubious eczema just  after  6 months could have a more accurate eczema diagnosis. Hanifin et Rajka diagnostic criteria for infants showed to be useful just after 6 months, since some of its criteria are evolutive.  All patients improved with hydrocortisone cream, but seborrheic eczema infants had a better  response and prognosis, with complete eczema resolution until 8 months. The presence of pruritus could be securely established just after 6 months of age.

Conclusions: Continuous follow up is indispensable for Infant atopic dermatitis differential diagnosis with seborrheic eczema. Eczema distribution and therapy response are the best predictors for differential diagnosis in infant eczema.