Mast cell tumors are tumors involving cells which contain granules of histamine. Patients with mast cell tumors experience chronic inflammatory symptoms due to circulating histamine. Antihistamines such as diphenhydramine may be helpful given long term though hydroxyzine could also be used. Hydroxyzine has an anti-nauseal side effect which makes it helpful in treating motion sickness. Hydroxyzine causes drowsiness in animals just as it does in people and can be used as a mild tranquilizer.
Hydroxyzine is a member of the piperazine class of antihistamines.
When different antihistamines are being tried out and one appears ineffective, it is felt that the subsequent choice should be of a different class to avoid the likelihood of another failure. Drowsiness is generally regarded as an undesirable side effect. At doses higher than the recommended dose, human patients complain of dry mouth and experience difficulty with urination. Animal patients experiencing a dry mouth may drink more water. In the treatment of allergic skin disease, antihistamines are felt to synergize with omega 3 fatty acid supplements and, as a general rule for this condition, it is best to use these medications together.