CHAPTER 18 Vulvar Dermatoses: the Eczematous Diseases

The eczematous diseases account for a very large proportion of all disorders occurring in the vulvar area. Most of the eczematous diseases are quite symptomatic and this leads to high demand for attention from patients and rapid patient dissatisfaction when the problem is not quickly recognized and appropriately treated.

The morphology of the eczematous diseases overlaps with that of the papulosquamous diseases (see Chapter 17). The three morphological features that the eczematous diseases share with the papulosquamous diseases include red color, overlying scale, and elevated papules and plaques. However the eczematous diseases do have three distinctive morphologic features that help to separate them from the papulosquamous diseases: (1) the presence of indistinct lesional margination; (2) evidence of epithelial disruption; and, in the special case of pruritic eczematous disease, (3) lichenification.

Lesional margination: Margination refers to the transition between normal and diseased tissue. Sharply marginated lesions have an abrupt transition such that one could place a pencil point at the exact border between normal and abnormal tissue. With indistinctly marginated lesions, the transition occurs over a matter of several millimeters. In this case, the margin of the lesions fades imperceptibly into the surrounding normal tissue and it is impossible to mark the exact point of transition. One can also consider the sharpness of margination by visualizing the contour of the lesion as seen in cross-section. A sharply marginated lesion would be quite square-shouldered whereas an indistinctly marginated lesion would demonstrate significantly sloped shoulders. Papulosquamous lesions have sharply marginated borders around the entire circumference of the lesion whereas eczematous lesions are indistinctly marginated over at least a major portion of their circumference.

Epithelial disruption: When the epithelial barrier layer is intact it allows no clinically perceptible passage of fluid in either direction across it. An intact epithelial barrier layer is found in the papulosquamous disease but it is disrupted in the eczematous diseases. There are five signs, any one or combination of which indicates the presence of epithelial disruption: (1) easily visible linear or angular erosions due to excoriation; (2) barely visible narrow erosions in the form of fine fissures; (3) a wet surface due to “weeping” or “oozing”; (4) crusting, due to the evaporation of surface water leaving dried plasma proteins. The color of crust is yellow (when no blood cells are present) and red, purple, or black (when blood cells are present); and (5) yellow scale, due to minimal fluid flow which colors existing scale rather than building up as crust.

Lichenification: When the skin of the palms and soles is chronically traumatized, it undergoes a protective response which we recognize as callus. Chronically traumatized tissue at other sites, due to chronic rubbing, also forms a protective response involving the thickening of the epidermis and the stratum corneum. This response, called lichenification, is characterized by three findings: (1) compacted scale; (2) exaggerated skin markings; and (3) palpable thickening. Lichenification is generally only encountered in the presence of atopic/neurodermatitis and its localized variant, lichen simplex chronicus.

Theoretically, the characteristic features described above would allow one to recognize readily the presence of an eczematous disease. Unfortunately, in the anogenital area, the presence of heat and sweat (with resultant maceration) leads to a great deal of background “noise” which can sometimes obscure the true nature of the process. Improvement of the environmental condition, treatment of any associated rubbing or scratching, and/or biopsy may be necessary to differentiate an eczematous disorder from a papulosquamous disorder.

Atopic/neurodermatitis and lichen simplex chronicus

Atopic/neurodermatitis and its localized variant lichen simplex chronicus are by far the most important of the conditions found in the eczematous disease category. In fact, this form of eczematous disease is so important that the entirety of Chapter 16 is devoted to this subject. A clinician faced with vulvar lesions possessing the morphology of an eczematous process (as defined above) that is accompanied by persistent scratching and rubbing is almost certainly dealing with lichen simplex chronicus. In such a situation the material in Chapter 16 should be reviewed as it will allow for confirmation of diagnosis and establishment of an effective therapeutic program.

Contact dermatitis

There are two forms of contact dermatitis: irritant and allergic contact dermatitis. The former is due to direct destructive effect by the contactant and is fairly common. The latter is due to a contactant-induced, immunologically mediated reaction and is uncommonly encountered.

Irritant contact dermatitis

Epidemiology and clinical manifestations

The exact prevalence of irritant contact dermatitis has not been established but most clinicians would agree that it occurs fairly frequently. This is particularly true when one considers the extremes of age in infancy and the elderly, where “diaper dermatitis” is almost inevitable. For the rest of the population the situation is less clear. Women in early and middle adult life are certainly exposed to many irritants but it is often unclear what role, if any, these are playing in terms of the patient’s presenting symptoms and signs. Irritant contact dermatitis can either arise de novo on normal tissue or may develop as a superimposed phenomenon on some other disorder.

Irritant contact dermatitis can be acute or chronic in type ¹. In acute contact dermatitis, the contactant causing the problem is so damaging that only one or two exposures are enough to create a marked inflammatory response. There is also only a short time period between the point of exposure and the development of the reaction. These two facts make the identification of the contactant quite easy. For patients who withhold history (such as those who are self-destructive and those with obsessive-compulsive behavior), the diagnosis may be less readily apparent. In the instance of acute irritant contact dermatitis, the involved tissue is quite red and often edematous. Pain is present, scale is minimal, and the surface may be eroded (Figures 18.1 and 18.2).

Figure 18.1 Deep redness with erosions (arrows) as a result of acute irritant dermatitis produced by fluorouracil applied to treat genital warts.

(Reproduced from P. J. Lynch and L Edwards Genital Dermatology (Fig. 5-11), New York: Churchill Livingstone; 1994.)

Figure 18.2 Harsh disinfectants have produced an exudative, vesicular, and edematous acute irritant dermatitis.

(Reproduced from P. J. Lynch and L Edwards Genital Dermatology (Fig. 5-12), New York: Churchill Livingstone; 1994.)

On the other hand, the development of chronic contact dermatitis is due to a less damaging contactant requiring multiple exposures over a longer time frame. In this situation, tissue swelling is minimal and redness, often with dusky or violaceous hues, is less intense (Figure 18.3). Fine cracks and fissures may be noted and the vulva may appear dry and chapped. Some scale is likely to be present. Symptoms are usually those of mild burning or irritation; itching is not usually a prominent feature.

Figure 18.3 The ongoing exposure of skin to urine and feces has produced a chronic irritant dermatitis manifested by dusky redness and edema of the vulva and perianal skin in this incontinent woman.

Diagnosis and differential diagnoses

Nearly all of the other papulosquamous and eczematous diseases have to be considered (Table 18.1). Sometimes it is difficult to separate irritant contact dermatitis from allergic contact dermatitis². The correct diagnosis depends on obtaining a thorough history of what the patient has been applying to her anogenital area. Unfortunately, patients are often forgetful about what they are using and also may be reticent or ashamed to list everything. For this reason, questions about what products are being used must be asked on multiple occasions. It is also helpful to ask the patient to go through her medicine cabinet and, at the time of the next visit, to bring in every topical agent that is found there.

Table 18.1 Irritant Contact Dermatitis

Diagnosis

Flat, dusky red, chapped, eczematous patches

History of products which overdry or macerate skin

History of excessive hygiene

Differential Diagnosis

Candida vulvitis

Allergic contact dermatitis

Atopic/neurodermatitis

Lichen simplex chronicus

Seborrheic dermatitis

Therapy

Identify and remove irritants

Low- (1% hydrocortisone) or medium-strength (0.1% triamcinalone) steroid ointments

Allergic contact dermatitis

Epidemiology and clinical manifestations

The prevalence of allergic contact dermatitis is difficult to determine. In those clinical settings where patch testing for women with vulvar dermatitis is carried out on a regular basis, about 50% (range 38–78%) of patients have developed one or more positive tests ^1,³. These patch tests were deemed clinically relevant in about 30% of all women with positive tests^1,^3,⁴. However, in clinics where patch testing is carried out infrequently, the percentage of positive patch tests, and hence the purported incidence of allergic contact dermatitis, is much lower. How much lower is difficult to say, but we believe it is less that 5%. At this point, it is not possible to explain this wide discrepancy.

The clinical appearance of allergic contact dermatitis is that of bright red, edematous papules and plaques (Figure 18.4). Scale is not prominent and may be absent. Pruritus is marked and excoriations may be present. An element of the itch–scratch cycle (lichen simplex chronicus) often develops, creating a confusing clinical picture.

Figure 18.4 Allergic contact dermatitis of the vulva. The patient intermittently used a topical medication containing neomycin, to which she was allergic.

Initial sensitization to an antigen takes 7–10 days but, once sensitization is present, reapplication of the antigen results in an inflammatory reaction within minutes to hours. For this reason, the appearance of allergic contact dermatitis to a new product is delayed for days but reapplication at a later time quickly causes symptoms and signs.

Diagnosis and differential diagnoses

The clinical appearance of allergic contact dermatitis can overlap with that of irritant contact dermatitis ² but brighter red color, presence of edema, lack of a chapped appearance, and prominent itching point more toward an allergic reaction (Table 18.2). Other eczematous diseases such as lichen simplex chronicus and seborrheic dermatitis are also similar in appearance. Even candidiasis and papulosquamous conditions, to include psoriasis and tinea cruris, need to be considered.

Table 18.2 Allergic Contact Dermatitis