Vulva Contact dermatitis

Contact dermatitis

Contact dermatitis is an inflammation of the skin resulting from an external agent that acts as either an irritant or an allergen. This reaction may be acute, subacute or chronic. Vulvar disease is often multifactorial and contact dermatitis of the vulva is frequently an important contributor. It is not usually the primary cause of vulvar problems but is often the compounding factor for patients complaining of vulvar itching, irritation and burning.

The two types of contact dermatitis are Primary irritant dermatitis and Allergic contact dermatitis

i. Primary irritant dermatitis results from prolonged or repeated exposure to a caustic or physically irritating agent. Anyone exposed to such a product often enough will have a reaction. This is a non-immunologic reaction. The skin is directly damaged by the irritant, for example urine, feces, and trichloroacetic acid.

ii. Allergic contact dermatitis results from a frank allergic reaction to a low dose of a substance. This is a type IV delayed hypersensitivity reaction to an allergen, for example poison ivy, neomycin or benzocaine.

Clinical Presentation: this is same for both types of reactions. Both cause a dermatitis reaction. The presentation will depend on how acute the reaction is. Varying degrees of itch, burning and irritation can occur. This can onset acutely or gradually. With an irritant there is a history of repeated exposure, for example chronic incontinence or repeated use of soaps or cleansers. One of the commonest problems here is chronic over-washing. The symptoms from irritant contact dermatitis can be sudden and dramatic, however, if the agent is caustic and burns, like the trichloroacetic acid which is used for destruction of genital warts. Allergic contact dermatitis can also be very acute with sudden onset of symptoms of itching and burning and can be very intense, especially with an allergen like poison ivy. On physical exam there can be an acute blistered erosive eruption with varying degree of crusting. Most of the time there are subacute or chronic changes with erythematous or dusky plaques and some scaling, often with secondary changes of excoriation, honey colored crusting (with or without secondary infection) or just dryness, scaling and erythema. Discoloration may occur.

Diagnosis: The morphology of the eruption must be defined and the history of exposure to all possible irritant substances or allergens is obtained. A biopsy may be necessary. To define allergic etiology, a dermatologist or allergist may do patch testing.

In diagnosing contact dermatitis, there are some tips that may be important:

i. The history of the contactant may be difficult to elicit, as the patient may forget or is unaware what they have habitually used. Keep asking questions.

ii. Irritant contact dermatitis is most common in those exposed to moisture because the skin gets macerated and the skin barrier breaks down from excessive moisture. Excess soap and water strip the skin of its protective barrier. Urine will cause a chemical burn and feces can cause an enzymatic burn. Sanitary pads can be irritating; the pad surfaces alone can be a problem and if they are not changed regularly the moisture further irritates the vulva.

iii. Patients with loss of estrogen have a weakening of the epidermal barrier and are more easily irritated

iv. Suspect allergic contact dermatitis when there is sudden onset of intense itching +/- vesiculation, erosion and weeping.

Treatment: The main treatment is to eliminate the contactant. One has to stop the irritant or allergen exposure. Topical corticosteroids such as triamcinolone 0.1% ointment can be used for 10-14 days. Nighttime sedation may help for sleeping. Antibiotics may be necessary for secondary infection. If the condition is very severe systemic cortisone either with prednisone 1 mg per kg given orally and decreased over 14 days or triamcinolone acetonide 1 mg per kg intramuscularly can be used.

Common Vulvar Irritants: soaps/cleansers, douches, medications, trichloroacetic acid, 5FU, spermicides, sweat, urine, feces, panty liners.

Common Vulvar Allergens: benzocaine (Vagisil), preservatives, neomycin (Neosporin), latex condoms, chlorhexidine (KY), lanolin, perfume, nail polish.