Dermatitis - specifically around eyes, nose, mouth
Alopecia
Enteritis (diarrhea, nausea/vomiting)
Neurological - including AMS, lethargy, hallucinations, paresthesias
Presents in the first week of life with:
Lethargy
Hypotonia
Vomiting
Presents later in life with:
Dermatitis
Neurological symptoms - ataxia, seizures, myoclonus, nystagmus
Ketoacidosis
Vitamin B7 deficiency
DDx involves genetic disorders with impaired carboxylation.
Vitamin B9 deficiency
Biotinidase Deficiency 
Vitamin B12 deficiency
Holocarboxylase Synthetase Deficiency 
Vitamin A deficiency
Carnitine Deficiency