Repeat allergy test?

[Ap2020]

I had an allergy blood test in May and it confirmed multiple moderate allergies.  I also began allergy shots.  Now six months later, I may be feeling a bit better but it's hard to know for sure.  When I wake up in the morning I still have quite a lot of mucus.  I'm told this results from dust mites, even though I have fully encased my bedding.  Dust mites, indeed, was one of the allergies -- dermat pteronyssinus --  for which I tested positive, but the other -- dermat farina -- was negative, though it was close to the "equivocal" level on the test.

The question: Is it possible my negative test for this one type of dust mites was a false negative, meaning, perhaps, that the shots are not covering everything?  Would it make sense to repeat the test?  

[David Tinkelman, M.D.]

These two types of mites often, but not always, show cross reactivity.  It is possible that the equivocally negative dermat farina was a false negative, and repeating it would cause no harm.  The first step would be to ask your allergist if the antigens in your shots just happen to include D. farinae, even  though the skin test was deemed negative.  If that is not the case and if there is a specific shot for D. farinae you should ask him/her if the addition of this to your current shot regimen might be appropriate.

Even if your current shots already include coverage for D. farinae, that coverage would not necessarily be clinically effective.  In that case, further attempts to identify the cause of your excessive mucous would be in order, as it might respond to additional pharmacotherapy.  It should not be assumed that this mucous is secondary to the D. farinae.  There could well be yet another, not yet diagnosed, allergic or non-allergic cause.

There is a drug called omalizumab (an anti-IgE antibody) that is approved for use in severe, otherwise unresponsive-to-treatment, asthma.  There have been reports, however that this drug is potentially effective for the management of rhinitis, but this is seldom considered to be appropriate use of this drug.

A combination of an inhaled nasal steroid, nasal washes (also referred to as nasal irrigation), with the addition of an anti-histamine is a much more accepted approach.

Good luck

[Ap2020]

Thank you for the thorough response.