In severe cases finger nails and lips may turn gray to bluish in colour in which of the following disease :-

Options

A. Pneumonia
B. Malaria
C. Typhoid
D. Filariasis

Answer

To solve the question regarding which disease causes severe cases where fingernails and lips may turn gray to bluish in color, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Symptoms**: The question mentions that in severe cases, fingernails and lips turn gray to bluish in color. This symptom is typically associated with a lack of oxygen in the blood, known as cyanosis.

2. **Identify Possible Diseases**: The question provides multiple options, and we need to analyze each one to see if they are associated with the symptom of cyanosis.
- **Pneumonia**: This is an infection that inflames the air sacs in one or both lungs, which can fill with fluid. Severe pneumonia can lead to reduced oxygen levels in the blood, causing cyanosis.
- **Malaria**: Caused by the Plasmodium parasite, it primarily affects red blood cells and does not typically cause cyanosis.
- **Typhoid**: Caused by Salmonella typhi, it primarily affects the digestive system and does not lead to cyanosis.
- **Filariasis**: Caused by parasitic worms, it primarily affects the lymphatic system and does not cause cyanosis.

3. **Conclusion**: Among the diseases listed, pneumonia is the only one that can lead to the symptoms described (gray to bluish nails and lips) due to its impact on the lungs and oxygen exchange.

### Final Answer:
The disease in which fingernails and lips may turn gray to bluish in color in severe cases is **Pneumonia**.