Dermatologists utilize various skin tests to diagnose skin problems, ranging from skin rashes and skin allergies to cancerous cells and non-cancerous growths. Skin testing for an allergy may involve us scratching your outer layer of skin, injecting a small amount of the suspected allergen under your skin, or sticking a patch of the allergen on your skin to test your reaction. We may use other tests to determine if you have an infection or a chronic skin condition, such as psoriasis or rosacea. If you have any suspicious moles or other skin growths, we’ll likely order a biopsy to determine if it’s cancerous or non-cancerous before recommending any skin treatments.