Final answer:
To investigate for bullous pemphigoid, methods such as darkfield or brightfield stain examination, serological testing, and VDRL-CSF test can be used.
Step-by-step explanation:
When investigating for bullous pemphigoid, there are several methods that can be used:
- Darkfield or brightfield silver stain examination of lesion tissue or exudate to observe physical changes.
- Treponemal and non-treponemal serological testing can be done to detect specific antibodies.
- VDRL-CSF test can be performed for neurosyphilis.
- Prenatal TORCH panel can also be considered as part of the investigation.