Lichen Simplex Chronicus
In contrast to many dermatologic conditions that may be described as “rashes that itch,” lichen simplex chronicus can be described as “an itch that rashes.” Most patients develop this disorder secondary to an irritant dermatitis, which progresses to lichen simplex chronicus as a result of the effects of chronic mechanical irritation from scratch-ing and rubbing an already irritated area. The mechanicalirritation contributes to epidermal thickening or hyperplasia and inflammatory cell infiltrate, which, in turn, leads to heightened sensitivity that triggers more mechanical irritation.
Accordingly, the history of these patients is one of progres-sive vulvar pruritus and/or burning, which is temporarilyrelieved by scratching or rubbing with a washcloth or some similar material. Etiologic factors for the original pruritic symptoms often are unknown, but may include sources of skin irritation such as laundry detergents, fab-ric softeners, scented hygienic preparations, and the use of colored or scented toilet tissue. These potential sources of symptoms must be investigated. Any domestic or hygienic irritants must be removed, in combination with treatment, to break the cycle described.
On clinical inspection, the skin of the labia majora, labia minora, and perineal body often shows diffusely reddened areas with occasional hyperplastic or hyperpigmented plaques of red to reddish brown (see Fig. 42.1A). One may also find occasionalareas of linear hyperplasia, which show the effect of grossly hyperkeratotic ridges of epidermis. Biopsy of patients who have these characteristic findings is usually not warranted.
Empiric treatment to include antipruritic medications such as diphenhydramine hydrochloride (Benadryl) or hydroxyzine hydrochloride (Atarax) that inhibit nighttime, unconscious scratching, combined with a mild to moder-ate topical steroid cream applied to the vulva, usually pro-vides relief. A steroid cream, such as hydrocortisone (1% or 2%) or, for patients with significant areas of obvious hyperkeratosis, triamcinolone acetonide or betamethasone valerate may be used. If significant relief is not obtained within3 months, diagnostic vulvar biopsy is warranted.
The prognosis for this disorder is excellent when the offend-ing irritating agents are removed and a topical steroid prepara-tion is used appropriately. In most patients, these measurescure the problem and eliminate future recurrences.