Ridley's The Vulva

Ultraviolet radiation (UVR) has been used to treat skin disease since ancient times. It is mainly used to treat psoriasis, but several other dermatoses will respond [25]. The wavelengths used in treatment are ultraviolet A (UVA) (320–380 nm) and ultraviolet B (UVB) (280–320 nm). Exposure to UVR induces direct DNA damage and a shift of the immune response to Th2.

In phototherapy with photochemotherapy (PUVA; psoralen and UVA), psoralen is either taken orally or applied topically to enhance the effect of the UVA. This treatment causes the most DNA damage and has carcinogenic potential. Its use has been reported in small studies in genital dermatoses [26]. However, it is limited in vulval disease as it difficult to expose the genital area to light in isolation, and there are concerns about the carcinogenic risk.

PDT relies on the interaction between a photosensitiser, oxygen, light, and the tissue affected [27]. The photosensitisers generally used are aminolevulinic acid (5‐ALA) or methyl aminolevulinate (MAL). These are applied to the lesion and reactive oxygen species are generated, which when activated by blue or red light cause cell death. It can be used systemically, but topical PDT is the most widely used. Only the abnormal cells which take up the photosensitiser are damaged so that the surrounding skin is unaffected, therefore giving good cosmetic results. It has been used to treat lichen sclerosus (LS), lichen planus (LP), HSIL, and extra‐mammary Paget’s disease.

The photosensitiser has to be left in place for a few hours so the whole treatment can be prolonged. Light exposure is often very painful, and there is a marked inflammatory reaction after.

Patient information on treatments is available at www.bad.org.ukand www.dermnetz.org. Last accessed September 2021.

1 1 Chen, Y., Bruning, E., Rubino, J. and Eder, S.E. Role of female intimate hygiene in vulvovaginal health: Global hygiene practices and product usage. Womens Health (Lond). 2017 Dec; 13(3): 58–67.

2 6 Kai, A. and Lewis, F. Long‐term use of an ultrapotent topical steroid for the treatment of vulval lichen sclerosus is safe. J Obstet Gynaecol. 2016; 36(2): 276–277.

3 7 Chi, C.C., Wang, S.H., Wojnarowska, F. et al. Safety of topical corticosteroids in pregnancy. Cochrane Database Syst Rev. 2015 Oct 26; (10): CD007346.

4 10 Hengge, U.R., Ruzicka, T., Schwartz, R.A. and Cork, M.J. Adverse effects of topical glucocorticosteroids. J Am Acad Dermatol. 2006 Jan; 54(1): 1–15; quiz 16‐8.

5 23 Edwards, D. and Panay, N. Treating vulvovaginal atrophy/genitourinary syndrome of menopause: How important is vaginal lubricant and moisturizer composition? Climacteric. 2016 Apr; 19(2): 151–161.

Gulshan Sethi

Pathophysiology

Clinical features

Diagnosis Amsel’s criteria Hay–Ison method Nugent score

Differential diagnosis

Complications

Treatment

Prognosis and follow-up

Resources

References

Bacterial vaginosis (BV) is the commonest cause of abnormal vaginal discharge in women of childbearing age, with a prevalence varying from 5% to 50%. It was found in 12% of pregnant women attending an antenatal clinic in the United Kingdom [ 1], and in 30% in women undergoing termination of pregnancy [ 2].

The pH of the normal vagina is preserved below 4.5. BV generally occurs as a consequence of a disturbance in the vaginal flora resulting in an increase in the pH to 6.0. This is associated with overgrowth of Gardnerella vaginalis and the other anaerobic species (up to a thousandfold), together with a reduction in lactobacilli.

The characteristic symptom of this condition is an offensive vaginal discharge, due to the production of amines such as putrescine, cadaverine, and trimethylamine that give off a characteristic fishy odour [ 3]. Vaginal inflammation is uncommon; hence, the term vaginosis is used rather than vaginitis. Symptoms may be exacerbated by factors which lead to an increase in vaginal pH such as douching, menstruation, and the presence of semen in the vagina. Although BV occurs more commonly in sexually active women, evidence for its sexual transmission is lacking, and treatment of the sexual partners of women with this condition does not prevent it from recurring [ 4, 5]

The diagnosis may be made by the fulfilment of Amsel’s criteria [ 6] or using the Hay–Ison [ 7] or Nugent [ 8] methods to examine the vaginal discharge.

To fulfil Amsel’s criteria, at least three of the following must be present:

1 Thin, white, homogeneous discharge.

2 Clue cells (vaginal epithelial cells covered with multiple gram‐variable organisms so that their edges are completely obliterated) on microscopy of wet mount ( Figure 9.1).

3 pH of vaginal fluid > 4.5.

4 Release of a fishy odour with 10% potassium hydroxide.

Microscopic examination to look for clue cells is not necessary for a diagnosis to be made using Amsel’s criteria as long as the other three factors can be demonstrated.

The Hay–Ison method of diagnosis uses microscopy and classes the results as the following.

Grade 1 (normal): Lactobacilli predominate. Figure 9.1 Clue cell.Source: Published in Wisdom, A and Hawkins, Diagnosis in Color: Sexually Transmitted Diseases, 2nd edn. Mosby‐Wolfe, London slide 283, p. 163, © Elsevier 1997.

Grade 2 (intermediate): Mixed flora with some Lactobacilli, but Gardnerella or Mobiluncus species also present.

Grade 3 (BV): Predominantly Gardnerella and/or Mobiluncus species. Lactobacilli are few or absent.

This is derived by estimating the relative proportions of different bacteria to produce a score between 0 and 10. A score of <4 is normal; 4–6 is intermediate; and >6 indicates BV.

The Hay–Ison and Nugent methods do not lend themselves easily to application outside of a specialist setting. Culture of vaginal fluid may grow G. vaginalis; however, this does not constitute a definitive diagnosis of BV as this organism can be found as a commensal.

There is a wide differential diagnosis including other infective and non‐infective causes (see Table 9.1).

Women with BV have an increased risk of many obstetric and gynaecological complications. These include pelvic inflammatory disease [ 9], post‐termination of pregnancy endometritis [ 10] and late miscarriage [ 11], preterm birth or rupture of membranes and postpartum endometritis [ 11], and an increased risk of infective complications after hysterectomy. In addition, in prospective studies, BV has emerged as a risk factor for acquisition of sexually transmitted infection, including human immunodeficiency virus (HIV) infection [ 12].

Table 9.1Differential diagnosis of bacterial vaginosis