Desensitization (medicine)

For medical purposes, desensitization is a method to reduce or eliminate an organism's negative reaction to a substance or stimulus.

For example, if a person with diabetes mellitus has a bad allergic reaction to taking a full dose of beef insulin, the doctor gives the person a very small amount of the insulin at first. Over a period, larger doses are given until the person is taking the full dose. This is one way to help the body get used to the full dose and to avoid having the allergic reaction to beef-origin insulin.

At the cellular level, administration of small doses of toxin produces an IgG response which eventually overrides the hypersensitive IgE response. A different mechanism is responsible for desensitization to antibiotics, which is performed over a shorter time course than desensitization to other allergies. In this form of desensitization, the patient is slowly exposed to a level of antibiotic that produces low-grade anaphylaxis. At the end of the procedure, the patient's mast cells have depleted their granular contents, and the patient cannot undergo any allergic response until these cells restore these contents.

In pharmacology, desensitization is the loss of responsiveness to the continuing or increasing dose of a drug. Also termed tachyphylaxis, downregulation, fade or drug tolerance. This may be an important area to consider for the future design of safer drugs.