Investigations in Vulval Disease

5Investigations in Vulval Disease

As with all disease, the investigation of any vulval problem will depend on the clinical differential diagnosis. The relevant investigations are detailed in subsequent chapters. This chapter discusses the basic investigations that may be needed when diagnosing a patient with vulval disease. Chapter 3 looked at the process of taking a vulval biopsy and histological interpretation.

Before taking any samples it is important to have all the necessary equipment available. Check any special transport requirements or laboratory rules. All samples taken for any investigation must be labelled correctly with the patient’s identifying details and the date and time collected.

Investigations for infection

Bacterial swabs

Sterile, cotton‐tipped swabs (Figure 5.1) are used to collect bacteria. These swabs can be used dry in the vulva and vagina. The tip can be gently rotated in order to obtain the best sample. In the laboratory, the swab is used to transfer the bacteria to an agar plate for culture and identification of the organism and then to establish antibiotic sensitivity where appropriate. Some bacteria need special transport media and conditions to grow and, if a specific infection is suspected, it is best to discuss this with the local laboratory before taking samples, as requirements may vary.

Figure 5.1 Bacterial swab.

Viral swabs

Swabs taken for the investigation of viral infection need special transport media. Swabs containing calcium alginate or wood will interfere with the isolation of viruses and are known to be toxic to herpes simplex. The correct swab must therefore be used and these are widely available (Figure 5.2a–c). When taking viral swabs, ideally an intact vesicle should be deroofed aseptically and the blister fluid swabbed, with the swab rotated on the base of the lesion.

Figure 5.2 (a) Viral swab and transport medium. (b) The swab is taken and then the tip is snapped off. (c) The tip of the swab is left in the transport medium.

Fungal scrapings

Skin scrapings are used in the diagnosis of superficial fungal infection. A simple scalpel blade or ‘banana’ scalpel (Figure 5.3) is used to scrape the scaly edge of a suspected fungal infection lightly (Figure 5.4). The scrapings are collected onto dark paper for transport to the laboratory (Figure 5.5).