依據藥理學來推理，不是沒有可能，而且在很多藥典上面，也可以看到Famotidine及Ranitidine的off label use有出現蕁麻疹治療
根據可以搜尋到的文獻，也建議在H1 blocker使用無效下，可以添加H2 blocker來控制無來由的過敏或是重積型的過敏症狀。
參考資料：Journal of Emergency Medicine. 9(5):378, 1991 Sep-Oct.
（1）Drugs 2004; 64 (22): 2515-2536 Chronic Urticaria
（2）British Journal of Dermatology (1987) 117, 81-88. Cimetidine and chlorpheniramine in the treatment of chronic idiopathic urticaria
（3）Clinical and Experimental Dermatology, 25, 186-190 Famotidine in the treatment of acute urticaria
（4）INTERNATIONAL JOURNAL OF DERMATOLOCY November 1984 H2 Blockers in Chronic Urticaria
（5）ANNALS OF EMERGENCY MEDICINE 36:5 NOVEMBER 2000 Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists
Results: There were significantly more patients without urticaria at 2 hours among the patients in the active group compared with those in the control group. Both groups had similar proportions of urticaria at baseline. Logistic regression models to predict resolution of urticaria, which accounted for baseline urticarial involvement, showed odds ratios in favor of the active group treatment. Similar findings were observed when the absence of both urticaria and angioedema was considered as the dependent variable. There was not a significant difference between the 2 groups with regard to the absence of erythema or angioedema (irrespective of the presence of urticaria) at 2 hours. Blood pressure and symptoms did not show differences between the 2 groups over time. Lower heart rates were observed
1 hour after treatment in the active treatment group (mean reduction 10 beats/min) compared with those found in
the placebo group (mean reduction 6 beats/min).
（6）Hritish joiirtutl of DermatoJogif (1993) 1 2 9 . 571 - 579. In dermographic urticaria H2 receptor antagonists have a small but therapeutically irrelevant additional effect compared with Hi antagonists alone
（7）Drugs 2005; 65 (3): 341-384 Second-Generation Antihistamines
（8）Allergy Net Successful combined therapy for refractory chronic urticaria in a 10-year-old boy
（9）Southern Medical Association Treatment Options for the Relief of Chronic Idiopathic Urticaria Symptoms