True wheat allergy
is rare, whereas wheat intolerance is quite common.
secondary to wheat allergy is unusual, and this might be a coincidence. You are more likley to have idiopathic urticaria that might get worse after eating certain foods and long-acting antihistamines for 4-6 weeks is recommended. If you continue to have itchy rashes, continue for 3 months. Fexofenadine
180mg/90mg and/or cetirizine
10mg is standard treatment options.
I hope that was useful.