Thanks for posting your query.
I can understand your concern for the symptoms.
First of all, the exact cause of seborrheic dermatitis is not properly understood and the prime cause is thought to be an yeast (fungus) called Malassezia. This fungus is one of the normal microscopic life forms that grow, along with certain bacteria, in your skin's oily secretion (sebum). Other than that, there are some aggravating factors like change of season (more in winters), stress and fatigue and immune status ( can be found in immunocompromised patients like HIV).
Although it is a fungus, but unlike other fungal infections, it is not contagious and is not considered an infection. Hence it is not transferred to the other people, towels, beddings etc.
Secondly it is mostly found in middle aged men or elderly men and may be found in infants less than one year of age in which it is called cradle cap. Hence if your child is school going then it is unlikely to be seborrheic dermatitis. However it is often hereditary and if you have been diagnosed with seborrheic dermatitis, then your child carries the risk of having it in future life during adulthood.
Moreover it causes redness and inflammation of skin with yellow patches or red, greasy skin covered with flaky white or yellow scales. Hence it is unlikely to be seborrheic dermatitis in your child’s case but confirmation needs to be done. Although dermatologist’s can diagnosed the condition by visual examination but differentiation can be done from psoriasis or eczema by a biopsy of the skin.
Hence get it examined from a dermatologist to rule out this condition in your child’s case.
Hope that this information helps and hope that you and your child get better soon.
Wishing you good health.
Mine is the only official diagnosis and my child 6 1/2 its not like mine. His cheeks are red at times but there's never any scaling. Though after bathing there was red above his eyebrow. So that combined with the dry skin inside the ear lobe made me think sd just very mild. His skin isn't oily either and he does have mild eczema at times. I have dry skin and had alot of acne as a teenager.
When would it be a cause for concern? So kids dont get it? Ive been tested as negative so no concern there unless cancer or something could cause it.
http://m.pediatrics.aappublications.org/content/115/1/e1.full , this was the study between 2 to 10 year olds that made me think it could be possible.