desensitize

Desensitize is a verb meaning to make or become less sensitive to a stimulus or agent, thereby reducing the intensity or likelihood of a response. The term is used in various fields, including psychology, medicine, immunology, and physiology. Its etymology derives from des- (removal) and sensitize (to make sensitive).

In psychology, desensitization reduces fear or anxiety through gradual exposure to a feared stimulus. Systematic desensitization combines exposure with relaxation training in a stepwise hierarchy, while exposure therapy uses repeated contact with the stimulus without avoidance to promote extinction of the fear response.

In physiology and pharmacology, desensitization describes decreased responsiveness of cells or receptors after repeated or sustained stimulation, a phenomenon known as tachyphylaxis or tolerance. Mechanisms include receptor phosphorylation and internalization, changes in receptor signaling, and downregulation. Clinically, desensitization affects dosing and may require drug rotation or pauses to restore sensitivity.

In immunology, desensitization can refer to allergen immunotherapy, where controlled exposure to an allergen reduces immune reactivity over time, and to drug desensitization procedures, where graded dosing allows temporary tolerance to a medication that previously caused a reaction.

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