Allergy testing kit. Dropper bottles used in skin prick tests for allergies. The bottles contain various solutions of allergy-provoking substances (allergens). These allergens are applied to punctures in the skin of a subject made by a needle. Any skin inflammation indicates an immune response, showing the patient may be allergic to that particular substance. Skin prick tests help to identify allergens responsible for specific allergies, allowing a treatment to be prescribed.