Skin prick test: Technique, interpretation, and applications

In the SPT, limited allergen amounts are introduced into the epidermis and non-vascular superficial dermis.These allergens interact with specific IgE bound to mast cells.Subsequent release of histamine and other mediators causes a visible "wheal-and-flare" reaction, which peaks at about 15 min and may take up to 45 min.[1] INDICATIONS OF SPTIndications for doing SPT are listed in Table 1.[2][3][4][5][6] A modification for testing of food items includes the doubleprick method or the prick-to-prick testing, which includes pricking of the fruit or vegetable, followed by pricking of the skin.This allows inclusion of fresh or seasonal fruits or vegetables that the patient may be allergic too especially if they are not included in the panel.It is not recommended in non-specific rash, which is not suggestive of atopic dermatitis, chronic urticaria without any suspected exogenous trigger, food intolerance without allergy, food intolerance without any allergic triggers, as in irritable bowel syndrome, chronic fatigue without allergy, or reactions to respiratory irritants such as smoke, perfumes, or fumes.[1,[7][8][9][10] CONTRAINDICATIONS SPT should be avoided in patients with persistent or severe uncontrolled asthma, pregnancy, since anaphylaxis can cause