Vulvar Pruritus and Lichen Simplex Chronicus

CHAPTER 16 Vulvar Pruritus and Lichen Simplex Chronicus



Peter J. Lynch


The skin and modified mucous membranes of the vulva are amply endowed with slow-conducting, unmyelinated sensory nerve fibers that terminate within the upper dermis and lower epidermis. When triggered, these nerve fibers carry either pain or itching to the sensory cortex. It is not completely understood why stimulation sometimes conveys pain and, at other times, itching. However, it has recently been shown that there is a subset of these nerve fibers that are physiologically restricted to the conduction of itching. Since the most common triggers for the stimulation of these nerve endings are the environmental factors of heat, sweating, friction, and other forms of mild trauma, it is easy to see why women are more likely to experience vulvar pruritus than pruritus at most other body sites.


Vulvar itching occurs in either a primary or secondary setting. In the primary form of pruritus, itching initially develops in normal-appearing, disease-free tissue. In the secondary form of pruritus, itching develops as a component of an underlying vulvar disorder such as candidiasis, lichen sclerosus, tinea cruris, psoriasis, or vulvar intraepithelial neoplasia (VIN). Primary pruritus can be viewed as “the itch that rashes” whereas secondary pruritus can be considered as “the rash that itches.” Since itching provokes scratching and rubbing in either setting, the clinical presentation may appear similar in both the primary and secondary setting.


When women present with the symptom of vulvar pruritus, clinical examination may or may not reveal abnormalities. Occasionally, early in the course of the problem, the vulva appears entirely normal. Most often, however, there is visible evidence of scratching and rubbing. Sometimes, as indicated above, there may also be changes suggesting the presence of an underlying condition such as candidiasis or one of the vulvar dermatoses. Only the primary form of itching will be reviewed in this chapter. Secondary pruritus, associated with underlying disorders, will be discussed as these conditions are covered elsewhere in the book. Nevertheless, it is extremely important to understand that treatment for itching and scratching is the same in both the primary and secondary setting. For that reason it is permissible and appropriate to initiate antipruritic therapy even when the two types of pruritus cannot initially be separately identified.


Unfortunately, the primary form of pruritus has been associated with major problems in terminology. At various times, in various countries, and by various specialists this form of vulvar itching has been termed “pruritus vulvae,” “eczema,” “atopic eczema,” “atopic dermatitis,” “neurodermatitis,” “hyperplastic dystrophy,” “squamous cell hyperplasia,” or “lichen simplex chronicus.” This has, not surprisingly, led to widespread misunderstanding and confusion. With this in mind, some discussion of these terms seems warranted.


“Pruritus vulvae” is, of course, self-explanatory but it is not very useful since a simple translation of a patient’s symptom into Latin does nothing to enhance understanding of the disorder. Moreover, it does nothing to differentiate the primary and secondary forms of pruritus. “Eczema” derives from the Greek word for “boiling out” and thus refers to acute, exudative inflammation of the skin. The term “eczema” used alone is sometimes substituted as a shorthand term for atopic eczema. But gradually the use of “eczema” has become less specific and today it is generally used as a synonym for “dermatitis.” Hence the two terms “atopic eczema” and “atopic dermatitis” are also now synonymous.


The terms “atopic dermatitis” and “atopic eczema” were originally only used when there was clinical evidence of atopy (allergic rhinitis, hayfever, or asthma) present in the patient and/or the immediate family. Later, the definition of atopy also included elevated total immunoglobulin (Ig) E, elevated antigen-specific IgE, and eosinophilia. Because of this restricted use, in instances where the eruption had the same clinical characteristics as atopic dermatitis but where atopy could not be identified, the term “neurodermatitis” was used instead. However “neurodermatitis” carries the connotation of psychological disturbance that may or may not be present. Moreover it is a term often troubling to patients. Increasingly the atopic and the nonatopic forms of primary pruritus are now being described as “extrinsic” (i.e., allergic) atopic dermatitis and “intrinsic’ (i.e., nonallergic) atopic dermatitis1.


The term “lichen simplex chronicus,” for all practical purposes, can be considered as the localized form of either extrinsic or intrinsic atopic dermatitis. It is a time-honored, morphologically descriptive term and it is not biased toward a specific etiology or pathophysiology. As such, “lichen simplex chronicus” is the term I have chosen to use for primary, localized chronic scratching and rubbing of the vulva.



Lichen simplex chronicus



Epidemiology and clinical manifestations


Pruritus, especially of the anogenital region, is one of the most common conditions encountered in both men and women. In a clinic devoted to vulvar disease, itching was the single most frequent presenting symptom, occurring in 70% of patients2. In another vulvar specialty clinic, “dermatitis” was found in 25% of patients and was, after lichen sclerosus, the second most common condition encountered3. And, in an audit of 114 nonneoplastic vulvar biopsies, lichen simplex chronicus was identified in 35% of the specimens and was the most frequent condition diagnosed4.



Patient history


By the time that a patient appears in the office, she usually indicates that her itching has been present for weeks or even months. She will also usually state that the level of the itching is severe and intractable. Most patients admit that they respond by scratching, even though they try as hard as possible not to do so. Some also acknowledge that “it feels good to scratch” while others find the itching so troublesome that they scratch until pain caused by the scratching replaces the sensation of itching. Still others are embarrassed by their scratching and either minimize the frequency with which they scratch or deny that they scratch at all.


In any event, when itching leads to scratching, the fingernails further stimulate the cutaneous nerve endings. This increases the sensation of itching and leads to even more scratching. In short order a vicious cycle of itching and scratching develops. The presence of this “itch–scratch” cycle is highly characteristic for the presence of lichen simplex chronicus and can be viewed as its single most defining characteristic.


Thus, in order to diagnose lichen simplex chronicus, one must demonstrate the presence of the itch–scratch cycle. This can be done by asking the patient whether scratching occurs at the subconscious level during the day and/or takes place at night while sleeping. Since patients may be unaware of nighttime scratching, the presence of this feature can also be identified through the confirmatory history of a bed partner or by the presence of blood flecks on the sheets or under the patient’s fingernails. I have called this nighttime scratching the “Penelope phenomenon” by analogy with Homer’s epic poem describing Odysseus’s wandering and subsequent long delay in reaching his home after the Trojan war. Penelope, the wife of Odysseus, continued to hope for his safe return and told her suitors that she would only consider remarriage after she finished weaving a traditional funeral shroud for her deathly ill father-in-law. With this in mind, she wove productively during the day but, to delay completion of the shroud, she arose at night and unraveled much of what she had woven the day before. The analogy, of course, refers to the fact that nighttime scratching undoes almost all of the benefit of a treatment program that only reduces scratching that occurs during the day.


Additional aspects of the patient’s history that should be sought include the presence of deleterious environmental factors such as sweating, the wearing of menstrual napkins, the rubbing of clothing, and the application of various medications. These environmental factors act much like scratching in that they may stimulate the nerve endings and thus play a role in establishing the itch–scratch cycle.


Psychological factors play an important part for many patients with lichen simplex chronicus5,6. Few patients volunteer the presence of anxiety and/or depression but, when directly asked, many will admit that their itching and resultant scratching are much worse when they are under stress. Based on long-term experience, I believe that these factors are frequently underrecognized and that they should be inquired about, and addressed if found, in all patients with lichen simplex chronicus.



Examination


Lichen simplex chronicus, as an eczematous disease, is characterized by the standard morphology of eczematous diseases: poorly marginated, red, scaling papules and plaques (Figure 16.1). Epithelial disruption in the form of excoriations, weeping, and crusting is present initially; lichenification and pigmentary alteration develop in patients with long-standing disease.


image

Figure 16.1 Red, lichenified, poorly demarcated plaques that are classic for lichen simplex chronicus.


(Reproduced from P. J. Lynch and L. Edwards Genital Dermatology (Fig. 5-1), New York: Churchill Livingstone; 1994.)


The papules and plaques are bright red initially but develop a dusky, brown-red color as time passes. Note, however, that in dark-skinned individuals, the red color may be masked by the patient’s normal brown pigmentation (Figure 16.2). The margination of the lesion, that is, the transition from abnormal to normal tissue, occurs somewhat gradually, resulting in indistinct margination. Scale is present but, because of the moisture normally present in the anogenital region, it may be visually inapparent. In this situation the scale may be only detectable as a slight roughness on palpation. As the course of the lichen simplex chronicus becomes more chronic, the surface, when moist, may whiten (see below) (Figure 16.3).


image

Figure 16.2 Thickness from rubbing and irregular erosions from scratching are typical of lichen simplex chronicus; as with most black patients, redness is not appreciated despite marked inflammation.


(Reproduced from P. J. Lynch and L. Edwards Genital Dermatology (Fig. 5-4), New York: Churchill Livingstone; 1994.)


image

Figure 16.3 This woman with lichen simplex chronicus exhibits redness, accentuation of skin markings of lichenification, scale, and fissuring. The thickened skin appears white from hydration.


(Reproduced from P. J. Lynch and L. Edwards Genital Dermatology (Fig. 5-7), New York: Churchill Livingstone; 1994.)


Excoriations are superimposed on the underlying inflamed red plaques and they may be superficial or deep. These scratch marks can be clinically differentiated from other causes of erosions and ulcers by their angular and linear shapes (Figure 16.4). Excoriations are accompanied by exudation (“weeping”) that leaves slightly yellow or even blood-colored stains on underwear. As the water portion of the exudate evaporates, the plasma proteins remain in place and form crusts. These crusts may be yellow or, if blood is also present, they may have red, blue, or black hues. Crusts almost always contain bacteria but a decision as to whether or not the bacteria represent infection, as opposed to colonization, must be made on other clinical evidence.


image

Figure 16.4

Related posts:

A Systematic Approach to the Dermatoses of Pregnancy The Papular and Pruritic Dermatoses of Pregnancy Pemphigoid (Herpes) Gestationis Physiologic Skin Changes of Pregnancy Vaginitis Disorders of Pigmentation

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Apr 29, 2016 | Posted by in Dermatology | Comments Off on Vulvar Pruritus and Lichen Simplex Chronicus

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