Dr. Brennan specializes in diagnosing and treating conditions such as hay fever, sinus trouble, asthma, food allergy, eczema, and hives. Other related conditions include itchy skin conditions, recurrent sinus infections, recurrent bronchitis and chronic cough. He provides testing and treatment for allergy skin testing, office pulmonary function testing, allergy injections (immunotherapy), and evaluations for stinging insect venoms and recurrent infections. Dr. Brennan is board certified in both Pediatrics and Allergy/Immunology. In addition to services at SCMC in Morris Dr. Brennan also provides Morris Allergy outreach services at Ortonville Health Services.