There are many possible causes of foot rashes. Athlete's foot is one of the more common causes. Additional causes include irritant or contact dermatitis, allergic rashes from shoes or other creams, dyshidrotic eczema (skin allergy rash), psoriasis, keratodermia blennorrhagicum, yeast infections, and bacterial infections.
Your physician can perform a simple test called a KOH, or potassium hydroxide for microscopic fungal examination, in the office or laboratory to confirm the presence of a fungal infection. This test is performed using small flakes of skin that are examined under the microscope. Many dermatologists perform this test in their office with results available within minutes. Rarely, a small piece of skin may be removed and sent for biopsy to help confirm the diagnosis.
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