Thank you for your inquiry.
Burning mouth syndrome is a very frustrating entity of unknown cause and without a specific therapy. Because of its frustrating nature, allergists are not infrequently asked to evaluate such patients, usually in the setting of a "last resort." However, there is no documented evidence that allergy plays a role in this disorder. In addition, I agree with you that a workup of immunodeficiency is not normally indicated in the evaluation of such a patient. And I agree with you that I don't think your patient is immunodeficient. I can't explain the apparent lack of response to diphtheria immunization, but don't think it has relevance to your patient since a deficient antibody response would not be expected to produce the clinical scenario you describe. Defects in cell mediated immunity would be far more likely.
Thus I might mention parenthetically that since you have embarked on an evaluation for immunodeficiency in relation to the presence of thrush, and since you have spent time and energy pursuing this workup, the evaluation is incomplete. Such a workup would be designed to evaluate cell-mediated immune function. I have copied for you below a table taken from our Practice Parameters on Immunodeficiency which lists the tests one orders for the assessment of cell-mediated immunity.
I mention this not that I feel such a workup is indicated, but since you may want to report back to the physician asking for the evaluation that you have completed an immune workup, in order to do so, you might consider the screening tests mentioned in the table from our practice parameter copied below.
Thank you again for your inquiry and we hope this response is helpful to you.
1. Sun A, Wu KM, Wang YP, Lin HP, Chen HM, Chiang CP. Burning mouth syndrome: a review and update. J Oral Pathol Med 2013 Oct; 42(9):649-55. doi: 10.1111/jop.12101. Epub 2013 Jun 16.
2. Spanemberg JC, Cherubini K, de Figueiredo MA, Yurgel LS, Salum FG. Aetiology and therapeutics of burning mouth syndrome: an update. Gerodontology 2012 Jun; 29(2):84-9.
Table. Cellular immune function
Flow cytometry to enumerate T cells and natural killer cells
Cutaneous delayed hypersensitivity
Enzyme assays (ADA, PNP)
FISH for 22q11 and 10p11 deletion
In vitro proliferative response to mitogens and antigens
Natural killer cell cytotoxicity
Cytokine production in response to mitogen or antigen stimulation
Expression of surface markers after mitogen stimulation
Source: Bonilla et al Practice parameter for the diagnosis and management of primary immunodeficiency: Ann Allergy Asthma Immunol 94; May 2005.
Phil Lieberman, M.D.