Allergy testing kit. Dropper bottles of allergens and sterile needles used in skin prick tests for allergies. The bottles contain various solutions of allergy-provoking substances (allergens). From left these are dog, two for Dermatophagoides (house dust mite), cat and negative and positive controls. Pollen and fungal spore allergens may also be tested. The 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 asthma or allergic rhinitis (hay fever).