Symptoms. Several types of histoplasmosis exist. The mildest form produces no signs or symptoms, but severe infections can be life-threatening. When signs and symptoms do occur, they usually appear three to 17 days after exposure and may include: 1  Fever. 2  Chills. 3  Headache. 4  Muscle aches. 5  Dry cough. 6  Chest discomfort.