What is Contact Dermatitis?
Contact dermatitis is a rash that results when a substance is applied to the skin. This can either be an allergic reaction or a burn. Examples of things that cause this are creams, ointments, gels, sprays, sanitary pads, dyes, or clothing. The rash may occur suddenly with blisters, itching and weeping or it may be a slower onset with redness, burning, and some swelling. Contact dermatitis of the vulva can occur alone or it can complicate any other vulvar skin condition like a yeast infection, psoriasis, lichen sclerosus, or eczema.
Any part of the vulva may be involved, from the mons pubis to the anus, even out onto the inner parts of the thighs. The extent of the rash will depend on where the offending product has touched the skin and how sensitive you are.
Types of Contact Dermatitis
Irritant Contact Dermatitis
This is the most common cause of vulvar contact dermatitis. It is a reaction to a caustic or irritating product that injures the skin. For instance a strong chemical burn from trichloroacetic acid used to “burn off” warts would cause an irritant contact dermatitis. Repeated exposure to mildly irritating products like soaps or gels can eventually burn the skin causing an irritated contact dermatitis. Urine and vaginal secretions touching the skin can also cause a similar problem. One of the most common causes of an irritant vulvar rash is cleansing or soap.
Allergic Contact Dermatitis
this is a reaction on the skin that develops due to your body’s allergic response to a substance, like poison ivy, applied to the skin surface. Possible causes of such a reaction in t e vulvar area are benzocaine (found in local anesthetic creams), neomycin (antibiotic creams), preservatives (in toilet wipes, emollients and prescribed steroid creams or ointments) or perfumes (widely used in many hygiene products). Like irritant contact dermatitis, these reactions may be mild with just minor redness, swelling and itching or severe with blistering, bright red swelling and severe discomfort.
Diagnosis is based on the history of exposure to the offending substance and the pattern of the rash. The diagnosis is made by your health care provider on the basis of the above factors. If the reaction is due to an allergy then special patch testing is done with a number of chemicals and placed on your back for 3 days to determine what is causing the reaction. This can be done by a dermatologist or an allergist.