Symptoms of PCP include a dry cough that produces little or no sputum, shortness of breath, and difficulty breathing. The disease may result in low levels of oxygen in the blood, giving the skin an ashen or bluish appearance. People with PCP typically have a low-grade fever and may also experience night sweats, weight loss, and fatigue; these symptoms may continue for weeks or months before respiratory symptoms develop. As the disease progresses, the small air sacs (alveoli) in the lungs may become inflamed, and the lungs may fill with fluid. Untreated, PCP is almost always fatal.