Chapter 39: Diseases of the Genitals and Perineum

A stroll down the pharmacy aisle is proof enough that genital symptoms plague our population. The sheer number of products such as cleaning wipes, douches, anti-itch sprays, and antifungal preparations is overwhelming. Many patients will go to great lengths to solve genital symptoms on their own, whether motivated by embarrassment, lack of access to medical care, or uncertainty as to which medical professional is best suited to treat the problem. Indeed, many clinicians also share this uncertainty. On the other hand, patients can be too certain of a diagnosis, for example ascribing any vulvar itching, burning, or discomfort to a yeast infection. Diseases are often diagnosed via telephone, and medications (especially antifungal treatments) are often prescribed without a physical examination.

Knowledge of normal genital anatomy, as well as normal variants of the male and female genitalia, must form the basis for any approach to diagnosing genital disease.

• Keratinized, hair-bearing skin is present on the scrotum and penile shaft in males and on the labia majora in females.

• Modified mucous membranes with a minimal keratin layer are present on the glans in males and medial labia majora and labia minora in females.

• True mucous membranes with no keratin layer are present on the urethral meatus in males and the vagina and introitus beginning at Hart's line in females.

In males, surgical removal of the prepuce (foreskin) decreases the incidence of penile cancers, genital warts, psoriasis, erosive lichen planus, lichen sclerosus, and several sexually transmitted infections including herpes simplex and human immunodeficiency virus (HIV).¹

Knowledge of anatomic boundaries, and the typical locations of certain conditions, may aid the clinician in distinguishing diseases with similar morphologic features. For example, involvement of the mucous membranes favors lichen planus over lichen sclerosus. Involvement of the intertriginous regions favors a candida infection, whereas sparing of the creases may implicate a contact dermatitis. A well-defined, scaly red plaque involving the scrotum may suggest lichen simplex chronicus, while tinea cruris, which is also red, scaly, and itchy, tends to spare the scrotum and favor the skin folds.

Normal variations of the genitalia commonly lead patients to seek medical attention, often in the setting of new-onset symptoms, or at the initiation of sexual activity. In the latter situation, these variants may be mistaken for sexually transmitted infections. This is often the case with pearly penile papules and vulvar papillae, which are present in more than one-third of uncircumcised males and premenopausal women, respectively; both are frequently misdiagnosed as genital warts.² Unlike warts, these papules are usually symmetric, exhibit domed rather than filiform tips, and have a discrete base. Prominent sebaceous glands (Fordyce spots) are also commonly mistaken for genital warts. These 1 to 2 mm yellowish papules occur on the modified mucous membranes, including the labia minora and distal shaft of the penis, and may coalesce to form thin plaques.³

Skin diseases of the genitals and perineum can be classified into four broad categories (see Table 39-1).

• Dermatitis

• Papulosquamous disorders

• Infection

• Cancerous and precancerous tumors

The diagnosis of genital disorders is made more challenging by the frequent coexistence of multiple disease processes. When a rash is noted elsewhere on the body, a unifying diagnosis is often sought. However, in the genital region, two separate diseases processes may be present. As an example, use of an over-the-counter cream to relieve itch due to lichen sclerosus may lead to a superimposed contact dermatitis.⁴

Yet another factor complicating the diagnosis of genital disease is the fact that few clinicians examine the asymptomatic external genitalia during routine examinations.³ Primary care clinicians often pay only passing attention to the external genitalia before proceeding to the internal exam, while dermatologists often leave this examination to the primary care clinician. Therefore, when a patient develops symptoms such as itch or pain, physiologic redness and normal variants may be perceived as abnormal.

Skin disease affecting the genitalia often presents differently than disease on nongenital skin. This is exemplified in psoriasis on the genitals, which lacks the classic silvery scale seen on dry, keratinized skin elsewhere. Lichen planus involving the genitals may manifest the characteristic purple, polygonal, pruritic papules. However, it may also present as pale annular plaques on the glans in men, or as shallow vulvar or vaginal erosions in women. A careful examination of the genitals and the rest of the skin and nails may reveal characteristic skin findings, such as nail pitting in psoriasis or oral mucosal involvement in lichen planus, thereby leading to the correct diagnosis.

• A thorough physical examination of genital and nongenital skin is important as many genital diseases such as lichen planus and psoriasis may have involvement elsewhere.

• Most genital disorders are usually diagnosed on the basis of the history and physical findings. However, laboratory confirmation is often needed to confirm the diagnosis of other diseases such as herpes simplex, perianal streptococcal disease, syphilis, and all suspected skin cancers.

• Potassium hydroxide (KOH) examination and/or fungal cultures should be performed for any rash in the inguinal fold areas or rashes with satellite pustules.

• A viral culture, polymerase chain reaction (PCR), viral culture, Tzanck smear, or a skin biopsy can be done to verify the diagnosis of herpes simplex. If these tests are negative consider ordering a mono spot test for mononucleosis which may present with genital ulcers.

• A skin biopsy should be done of tan to black pigmented lesions and lesions suspicious for in situ or invasive carcinomas. A biopsy may also be needed to confirm the diagnosis of papulosquamous disorders and warts.

• Patch testing can be considered for any rash in which allergic contact dermatitis is suspected.

Management

One of the primary, and most basic, management strategies is simplifying the treatment regimen. As mentioned above, many patients experiment with various over-the-counter remedies before presenting to a clinician, and develop extensive hygienic routines, which often do more harm than good. The patient should be instructed to wash with warm water, using the fingers, and refrain from applying anything to the genital region other than the prescribed treatments. Pure petrolatum jelly may be used for lubrication. If there is chronic irritation due to incontinence, or skin fold occlusion due to obesity, a barrier ointment may be indicated. When possible, ointments should be used in lieu of creams or gels, which have greater potential to irritate the skin.⁴ Preservatives and additives in the latter can also elicit contact dermatitis.

When prescribing a potent topical corticosteroid, such as clobetasol ointment, a clinician may preemptively treat fungal and yeast overgrowth with an agent such as oral fluconazole. A single oral dose of 150 to 200 mg fluconazole is often preferred over topical azole treatments due to the high incidence of irritation caused by the latter.⁴ The mucosal surfaces are relatively resistant to the adverse effects of topical steroid medications, whereas the keratinized skin, especially the skin folds and medial thighs, are prone to develop steroid atrophy and striae. When possible, the patient should be asked to demonstrate correct application of topical treatments, using a handheld mirror. This will insure that treatments are applied to the correct region, and in proper amounts.

It is important to address quality of life issues related to genital disorders, which can include, depression, dyspareunia, chronic pain or pruritus, and the many concerns related to sexually transmitted diseases.⁴

Patient Information

• Centers for Disease Control and Prevention (CDC) Sexually Transmitted Diseases: www.cdc.gov/std/

• International Society for the Study of Vulvovaginal Disease (patient education section): www.issvd.org

• The National Vulvodynia Association: www.nva.org

• American Cancer Society (penile cancer): www.cancer.org

The online learning center at www.LangeClinicalDermatology.com has clinical self-assessment questions for this chapter.