Imiquimod is a topical immunomodulatory therapy with TLR7 agonist-like activity. Very low serum concentrations have been found in patients who are using Imiquimod and it is thought to have minimal skin absorption. The literature regarding contraindications for allergen immunotherapy in the setting of immunomodulatory therapy is limited and conflicting, but papers mention relative or no contraindication to AIT depending upon the immunomodulator; agents that significantly inhibit the immune system are of concern. An EAACI position paper indicated that “there is no published or documented theoretical interaction between (pharmaceutical or other) treatment of an underlying malignant disease and AIT.” Given that imiquimod is thought to have little absorption beyond the dermis, it seems reasonable to initiate AIT after a thorough discussion with your patient.
Pitsios C et al. Clinical contraindications to allergen immunotherapy: an EAACI position paper. Allergy 70(2015):987-909.
Pitsios C et al. Contraindications to immunotherapy: a global approach. Clinical Transl Allergy 9 (2019): 1-10.
I hope this information is helpful to you and your patient.
Jacqueline A. Pongracic, MD, FAAAAI