Dangerous headache if ignored

Dangerous headache experienced by 48 years old male

​It started with itchiness around the left eye and the itchiness spread to the forehead. 4 days later, headache occurred on his left head. 7 days after the first itchiness, it worsened and became severe squeezed pain in his left head. He went see a doctor and was diagnosed as meningitis.
 
Meningitis is an acute inflammation of the protective membranes covering the brain and spinal cord, caused by infection with virus, bacteria or other microorganisms. If the proper treatment is delayed, it can become serious condition, resulting in aftereffects such as a long-term dementia.
 
Shingles that is caused by a herpes virus causing chickenpox as well is characterized by a painful skin rash with blisters.
 
Why does shingles cause meningitis?
 
A herpes virus causing chickenpox doesn’t disappear even after chickenpox gets better. It remains in the deep part of nerves and lives in a dormant state even if the person becomes an adult. A few decades later when the person’s immune system is weak, the dormant herpes virus is active again and causes rashes and blisters of a belt-like pattern. Shingles mostly occur at the age of 50-70s which the immune system becomes weaker. The symptoms of shingles usually appear on the skin, but sometimes the virus is activated deep inside nerves and spreads along the nerves, causing inflammation in the body. In that case, it is difficult to diagnose as shingles, leading to the delay of the detection. Lack of characteristic symptoms delays the detection of shingles, resulting in meningitis.
 
The trigeminal nerve is a nerve responsible for sensation in the face and motor functions such as biting and chewing, which is the largest nerve in the brain and around the face. When the trigeminal nerve is damaged by a herpes virus, strong headache occurs, but the lack of characteristic symptoms appearing with shingles delays the detection, sometimes resulting in meningitis or resulting in facial neuralgia which is very painful or facial paralysis. In the worst case, it results in encephalitis which is an acute inflammation of the brain.