Pickelhaube, Shell Fragments

The leather helmets offered virtually no protection against shell fragments and shrapnel, which caused wounds that were common during that conflict. Furthermore, the spike often extended over the top of the trench, indicating the location of the helmet-wearing soldiers inside the trench and sometimes enemy soldiers would deliberately target the spike to shoot it off to antagonize and/or intimidate German soldiers . These may have been reasons why a version with a detachable spike was introduced in 1915. Beginning in 1916, the Pickelhaube was slowly replaced by a new German steel helmet (the Stahlhelm ) intended to offer greater head protection from shell fragments. After the adoption of the Stahlhelm the Pickelhaube was reduced to limited ceremonial wear by senior officers away from the war zones. With the collapse of the German Empire in 1918, the Pickelhaube ceased to be part of the military uniform, and even the police adopted shakos of a Jager style. In modified forms the new Stahlhelm helmet would continue to be worn by German troops into World War II.

Source: Wikipedia > Pickelhaube