How Long Does a Skin Test Typically Take?

The skin test generally takes between 15 and 20 minutes. Generally speaking, if a patient needs intravenous drip or intramuscular injection of certain drugs, it may cause allergies, so a skin test is needed before use. Commonly used drugs include penicillin, some cephalosporins, or tetanus antitoxin. Generally, the drug is prepared at a relatively low concentration, and 0.1ml is injected into the inner side of the patient's forearm. The condition of the injection site is observed after 15 minutes. If the patient does not experience symptoms such as palpitations, chest tightness, or decreased blood pressure during the observation process, and there is no enlargement of the flare or pseudopodia at the injection site, the skin test result is considered negative, and the drug can continue to be used. Skin tests are actually quite common, and their significance is to determine whether the patient is allergic to the medication. Before performing a skin test, it is essential to ensure that the drug dosage is administered under the guidance of a nurse and conducted at the appropriate site, to minimize the risk of extensive skin allergies due to improper site selection. Although severe allergic reactions to skin tests are rare, they can occur, and it is important to be prepared for such situations. Skin tests should generally be conducted in hospitals or community clinics that have resuscitation facilities. Skin tests cannot be performed if there is dermatitis or eczema infection on the skin surface. Additionally, it is crucial to thoroughly understand the patient's medical history before performing a skin test. For instance, if the patient has recently taken immunosuppressants or antihistamines, they may not be suitable for a skin test. Administering a skin test in such cases may lead to coagulation dysfunction or severe systemic allergic reactions. The results of skin tests are generally accurate. After a skin test, the patient may experience mild bumps or varying degrees of redness and swelling on the skin surface. The doctor will assess the severity of the allergy based on the extent of redness and swelling. However, improper injection techniques, such as the injection of a small amount of air, may also cause allergic reactions on the skin surface.