Therapeutic Injection
Two major categories of vulvar injections for the alleviation of debilitating symptoms associated with dystrophic disorders are as follows: (1) alcohol injection for the relief of pruritus (not pain), and (2) dexamethasone (Decadron) injection for the relief of chronic inflammatory conditions (e.g., lichen sclerosus) and for the relief of chronic pain (pudendal neuralgia).
Alcohol Injection
Chronic pruritus that is unresponsive to topical medication (e.g., steroids) or retinoids is an indication for alcohol injection (Fig. 79–1). The criterion for injection to deaden the nerves is essentially the failure of conservative therapeutic measures to control vulvar itching. Patients should be warned that a complication of this type of treatment is neuropathy manifested by burning pain. Injection of an excessive volume of alcohol, as well as subcuticular injection, can and will cause tissue slough and possibly necrotizing fasciitis.
The patient is placed in the dorsal lithotomy position under general anesthesia. The area to be injected is divided into a grid, with all intersections 1 cm apart. The entire area may be large (i.e., encompassing the whole vulva) or limited to a single side. The grid is drawn after the vulva is prepared with hexachlorophene (Phisohex) or povidone-iodine (Betadine). A sterile surgical marking pen is the most convenient device for this task (Fig. 79–2). A 1-mL tuberculin syringe fitted with a 27-gauge needle is utilized for injection. Absolute alcohol is drawn up into the syringe. At each intersecting line, 0.1 mL of alcohol is injected into the subcutaneous fat (Fig. 79–3). The injection destroys the fine cutaneous branches of the perineal nerves, resulting in anesthesia to the vulva. The vulva is perceived by the patient as numb.
Dexamethasone Injection
The current treatment of choice for the relief of pruritus associated with lichen sclerosus is 2 mg of dexamethasone diluted to 10 mL with 0.25% bupivacaine. Serial injections also appear to arrest the progress of the inflammatory reaction and subsequent scar formation associated with lichen sclerosus. Injections are given in the office weekly, then biweekly, then monthly.
