Stomatitis and recurrent oral ulceration: is a full blood screen necessary?

A full haematology screen was carried out on 398 patients under investigation for recurrent oral ulceration or stomatitis. Thirty-three patients were found to have lowered serum folate and/or red cell folate levels without iron deficiency. Of these only six were found to have a mean corpuscular volume (MCV) outside normal limits or to have recognisable erythrocyte abnormalities. No correlation was found between serum or red cell folate levels and the MCV. Eighteen patients were found to have lowered serum B12 levels without iron deficiency, of these seven were found to have a MCV outside normal limits. A significant negative correlation was found between serum B12 levels and the MCV. It is concluded that haematological screening in these cases should include estimations of serum folate, red cell folate and serum B12 levels even in the face of an apparently normal peripheral blood film.