American Elm Shortage

American Elm is dying from Dutch Elm Disease. This may explain the concentrate shortage many practices and antigen suppliers are experiencing.

To help, there are many other elm species that are more or less resistant to this fungal disease and still cause allergic symptoms.  There is little cross-reactivity outside the elm family, so the best bet to overcome the shortage and help your patients is to substitute another elm species for allergen testing and immunotherapy.

Several Elm species are commercially available, including Slippery Elm and Chinese Elm.  Other options to consider include Mulberry, Hemp, and Hops — all closely related.  None of these substitutes are going to be exact matches, either for antigen profile or for potency.  Additionally, you can discuss further with the pharmacist at your Antigen source company to identify the most readily available cross-reactive option.  

Whichever you choose to use to replace American Elm will require mandatory vial testing for each patient who is switched to the new antigen. Best option to consider when replacing American Elm for Chinese Elm on your mixing board is to cut back one 5-fold dilution (5-fold) and then do a vial check.  Retesting is not necessary.  

For those with patients on monthly maintenance injections, you may need to re-escalate. With the recommendation of  a 1:5 dilution with the addition of the new Elm product, that implies the need for re-escalating back to the maintenance dose. If the patient is on monthly injections, and you use the standard AAOA escalation, it would take nearly 2 years to get back up to full maintenance dose or the patient will need to go back to weekly injections for five months until get back to full maintenance. You may want to consider a more rapid weekly re-escalation for a patient already on monthly maintenance, such as 0.1, 0.2, 0.3, 0.4, and 0.5 , which would cut down on the time to get back to full maintenance. This should be reasonably safe due to the cross-reactivity.