Bronchitis, Light micrograph (LM) of a section through bronchi filled with necrotic debris and purulent exudative material. The residual bronchial mucosa and surrounding bronchial wall contain a neutrophilic infiltrate. Bronchitis is temporary inflammation of the airways that causes a cough and mucous. It lasts up to 3 weeks. It can affect people of all ages, but mostly happens in children under the age of 5. It's more common in winter and often comes on after a common cold, sore throat or the flu. Magnification: x100 when printed at 10 centimetres wide. Human tissue.