Vulvar contact dermatitis

　　1. Etiology

　　Contact dermatitis is a dermatitis that occurs after the skin comes into contact with certain sensitizing or irritant substances, and it is mostly acute. It can be divided into two types according to the etiology: primary irritant dermatitis and allergic contact dermatitis.

　　Primary contact dermatitis is caused by strong irritants to the skin such as acids and bases, or other substances such as strong disinfectants, potassium permanganate that has not been completely dissolved during vaginal irrigation, and so on. Allergic contact dermatitis can be caused by exposure to sensitive substances by some individuals, such as vulvar contact with deodorant spray, contraceptives (condoms, birth control pills), dyed clothing, anesthetics, or locally applied antibiotics (especially penicillin) and other agents, which can all lead to dermatitis.

　　It is now known that there are more than 2800 allergens that can cause ACD, mainly including:

　　1. Animal: toxins, hair, down products, etc. of animals.

　　2. Plant: leaves, stems, flowers, fruits, seeds, and juice of plants. Common ones include lacquer, nettle, fig, ginkgo, mango, etc.

　　3. There are many chemical types, mainly including metal products such as nickel and chromium; household products such as detergents, brighteners, leather, plastics, and rubber products; cosmetics such as blush, perfume, hair dyes, etc.; and topical drugs. Common allergens in ACD of the female vulva include sanitary napkins, suppositories, perfumes, topical contraceptives, etc. Contact between couples can also lead to mutual sensitization.

　　Second, pathogenesis

　　1. In acute dermatitis, the histopathology shows edema between and within epidermal cells, up to spongiosis, vesicles, and bullae within the epidermis. There is infiltration of lymphocytes and neutrophils within the epidermis, with cells mainly concentrated within vesicles. The superficial connective tissue of the dermis is edematous, the blood vessels dilate, and there is focal infiltration of lymphocytes around small vessels, and sometimes a few neutrophils and eosinophils.

　　2. In subacute dermatitis, the histopathology shows edema and spongiosis in the epidermal cells, a few vesicles, mild epidermal thickening, and varying degrees of parakeratosis. There is a significant infiltration of lymphocytes around the blood vessels in the dermis.

　　3. In chronic dermatitis, the histopathology shows hyperplasia of the stratum spinosum, significant elongation of the epidermal papillae, and hyperkeratosis and parakeratosis. There may be mild intercellular edema in the epidermis, mild perivascular lymphocytic infiltration in the superficial dermis, and a small number of eosinophils and fibroblasts. The number of capillaries increases, and the endothelial cells swell and proliferate.

　　Primary Irritant Contact Dermatitis (ICD): The contact substance itself is strongly irritating to the skin, and anyone who contacts a certain concentration of the substance can develop a non-immunological skin inflammatory reaction. Primary irritation can be divided into two types: one is strongly irritating, with the disease developing shortly after contact, such as dermatitis caused by strong acids and alkalis; the other is weakly irritating, with the disease developing after a long period of contact, such as dermatitis caused by detergents, organic solvents, etc. Common causes of ICD in the vulva include highly concentrated disinfectants and preservatives, such as potassium permanganate solution, and some irritant topical drugs, such as podophyllotoxin, tretinoin, lactic acid, salicylic acid, etc. Factors affecting ICD include not only the physical and chemical properties, concentration, amount, contact time, and manner of the irritant itself, but also host factors such as age, gender, race, genetic background, and location, as well as local environmental factors such as temperature, humidity, friction, and pressure. Some literature reports that the A allele and AA genotype are significantly increased in the population prone to ICD.

　　Allergic Contact Dermatitis (ACD): The contact substance itself is non-irritating and non-toxic. Most people do not develop the disease after contact, but only a few sensitive individuals develop hypersensitivity reactions at the contact site of the skin and mucosa after a certain incubation period.

　　ACD is a delayed-type hypersensitivity mediated by T cells, in which T cells, keratinocytes, Langerhans cells, macrophages, vascular endothelial cells, and mast cells are involved. The pathogenesis is complex, and the following is a summary.

　　(1) Induction phase: The allergens that cause ACD are mostly haptens, which combine with carrier proteins on the cell membrane of epidermal cells to form complete antigens and obtain immunogenicity. The complete antigen is recognized, phagocytosed, and digested into peptide fragments by Langerhans cells (LC) in the epidermis, and then combined with MHC class II antigen molecules on the surface of LC to form antigen-MHC complexes. The LC carrying the antigen is transported to local lymph nodes through lymphatic drainage and presented to CD4+ T cells. As the LC migrate from the epidermis to local lymph nodes, their antigen processing activity gradually decreases while their immunostimulatory activity gradually increases. This maturation process of LC is considered a key factor in effectively inducing skin allergic reactions. This process is influenced by TNF-α, IL-1, and GM-CSF. In the process of presenting antigens to CD4+ T cells, the T cell receptor of CD4+ T cells must simultaneously recognize the antigen and the MHC class II antigen molecule complex to accept the antigen presented by LC and become activated, which is MHC restricted. In this process, LC also expresses ICAM-1, LFA-3, B7t, and other adhesion molecules, which bind to LFA-1, CD2, CD28 on the membrane of lymphocytes, respectively, to complete the sensitization reaction as the second signal.

　　(2) Activation phase: After sensitization, when the body is exposed to the same antigen again, after the induction phase, the antigen is transferred to specific CD4+ T cell sensitized cells. After CD4+ T cells recognize the antigen, they can cause cell differentiation and proliferation, and release a series of cytokines; IL-2, IFN-γ, GM-CSF, IL-3, IL-4, TNF, which promote T cell proliferation, expand the immune response, activate cytotoxic T cells, natural killer cells, and macrophages. This results in epidermal spongiosis and dermal inflammatory cell infiltration, capillary dilation, and increased permeability. Epidermal cells are damaged, leading to the acute dermatitis manifestation of papules, blisters, and even bullae.

　　After contacting some irritant substances on the vulva, there is a feeling of heat, pain, and itching at the contact site. Examination shows local skin erythema, rash, and blisters. In severe cases, necrosis and ulcers may occur, and allergic dermatitis may occur at the site of contact with allergens. If the cause can be removed early and appropriate treatment is given, it can be healed quickly; otherwise, it may lead to complications such as secondary infection and eczematous dermatitis.

　　Due to the loose and thin skin of the vulvar area, rich nerve endings, and difficulty in ventilation, rashes occurring on the vulva are more severe than those on other parts of the body. The affected area often shows significant swelling, with a feeling of severe itching or burning sensation, and a sense of distension and pain.

　　I. Irritant contact dermatitis (ICD)

　　1. Acute irritant contact dermatitis:Caused by strong irritants, common irritants that can cause acute vulvar ICD include: high-concentration disinfectants, dimethyl sulfoxide, podophyllotoxin, retinoic acid, and others. Local manifestations include erythema, edema, blisters, bullae, and even necrosis. The vulva, labia minora, and clitoris present localized edema without distinct margins, with skin皱纹 disappearing, and a sense of pain or burning sensation felt.

　　2, Irritant reaction:Mild skin damage that has not reached the extent of dermatitis is a刺激性反应. The skin lesions are single and can manifest as vulvar, labia majora erythema, rough skin, dry desquamation, long-term contact with skin thickening, and occasionally may further develop into cumulative ICD. Such irritants include hygiene products, soap, external washing drugs, ethanol, hydrogen peroxide, and so on.

　　3, Subjective irritant reaction:It refers to the vulvar irritation, burning sensation, and pain induced by some chemicals without skin damage such as erythema and edema. Histological examination usually shows no change, and subjective symptoms vary from person to person. Common irritants include hygiene products, external medicaments, suppositories, perfumes, urinary fistula, and wearing non-ventilated synthetic underwear can increase local humidity and heat, leading to itching.

　　4, Cumulative dermatitis:Repeated subthreshold stimulation by various weak irritants can lead to cumulative ICD. Initially, there may be vulvar itching, pain, dryness, erythema, and desquamation. After repeated contact with irritants and reaching a certain stimulation threshold, clear skin lesions of irritant dermatitis may appear. Long-term itching and scratching can cause the vulva and labia majora skin to become significantly lichenified, the clitoris and labia minora may become hypertrophic, and histological examination may show skin thickening and inflammatory cell infiltration. The intensity of the reaction varies due to individual differences in skin sensitivity. Due to repeated contact with irritants, the skin barrier function cannot be repaired in time, resulting in a longer healing time and various prognoses. Such irritants are mostly detergents, chemical solvents, and so on.

　　5, Dry eczematous dermatitisLong-term use of potassium permanganate solution, benzalkonium chloride solution for external washing, or excessive use of soap can cause vulvar dryness and itching.

　　6, Post-traumatic irritant dermatitis:When the vulva is macerated, eroded erythema, or acute ICD has not healed, and刺激性皮炎 occurs again, leading to erythema, papules, vesicles, vesicular papules, and desquamation. Subsequently, it may develop into a discoid eczematous reaction. If there is secondary infection, it will be more complex and heal more slowly.

　　Second, allergic contact dermatitis

　　Mild cases may present with clear, faint erythema at the vulvar contact site, with slight edema and papules or vesicles. Severe cases can develop bullae, large bullae, erosion, exudation, and scab formation. The labia majora and clitoris may show localized edema without clear edges, the skin may appear shiny, and the skin creases may disappear. Acute ACD usually heals within 1 to 2 weeks after removing the allergen, but if the allergen is continuously contacted, the skin lesions may recur and transform into chronic hypertrophic damage with hyperpigmentation, which is difficult to heal. Common allergens include sanitary napkins, suppositories, external medicaments, contraceptives, perfumes, nail polish, and metal nickel on clothing.

　　To recover and protect the skin barrier function, the skin of the vulva is thin and delicate, and the skin barrier function is damaged during dermatitis, so it is necessary to use locally applied medicaments with nutritional protection. It is forbidden to use irritant external medicaments and to avoid all possible treatments that may irritate the skin, such as excessive hot washing, scratching, maintaining the vulva clean and dry, wearing loose and breathable underwear, and not using inferior hygiene products.

　　Patch test is an auxiliary diagnostic method for determining the body's变态反应. Prepare appropriate concentrations of solutions, emulsions, ointments, or use the original substances directly as reagents according to the nature of the test substances. Soak the test solution with 4 layers of 1cm2 size gauze, or place the test substances on the gauze, place it on the flexor side of the forearm, cover it with a slightly larger transparent glass paper, and fix it with rubber cement. After 48 hours, remove it, which can induce local skin reactions, and read the results according to the local skin manifestations at 72 hours.

　　One, dietetic recipe for vulvar contact dermatitis

　　1. Carp and Red Bean Soup

　　Composition: 1 carp, 60g of red beans.

　　Usage: remove the head, tail, and bones of the carp, and cook the meat with red beans until the beans are soft. Take it in two doses.

　　Indications: for those with excessive leukorrhea and damp heat with toxicity.

　　2. Poria Cocos and Glutinous Rice Porridge

　　Composition: 30g of Poria cocos (ground powder), 30-60g of glutinous rice.

　　Usage: first cook the glutinous rice into porridge, add the powder of Poria cocos when it is half cooked, mix well, and cook until the rice is done, and take it on an empty stomach.

　　Indications: those with spleen deficiency and dampness in traditional Chinese medicine.

　　3. Kelp and Mung Bean Porridge

　　Ingredients: 30 grams of kelp, 30 grams of mung beans, appropriate amount of sugar, 100 grams of glutinous rice.

　　Preparation method: first wash the kelp and cut it into pieces, soak the mung beans for half a day, wash the glutinous rice clean, and cook them into porridge. Add sugar for seasoning when it is about to be cooked.

　　Usage: take it twice a day in the morning and evening, and it is advisable to continue eating for 7 to 10 days.

　　Its effect is to clear heat and detoxify, and relieve heat through diuresis. It is suitable for vulvar itching.

　　4. Coix Seed and Red Date Porridge: 30g of coix seed, 10 red dates, 50g of rice.

　　Wash and cook them together into porridge for consumption. It has the effect of clearing heat, invigorating the spleen and stopping itching.

　　5. Polygonum multiflorum and mulberry sesame porridge: 30g of Polygonum multiflorum, 10g of mulberry fruit, 10g of black sesame, 50g of rice.

　　Wash and cook them together into porridge for consumption. It has the effect of nourishing blood, moistening the Yin and stopping itching.

　　6. Steamed pork liver: 60g of pork liver, 30g of horsewhip grass.

　　Cut the pork liver and horsewhip grass into small pieces and mix them well, put them in a covered bowl, and steam them in a steamer for 30 minutes. Take it all at once. It has the effect of clearing heat and removing dampness.

　　Two, the diet of vulvar contact dermatitis is good for the body

　　1. Eat more foods rich in protein and sugars. For example: milk, soy milk, eggs, meats, etc.

　　2. Drink more water and eat more fresh fruits and vegetables. Such as: apples, pears, bananas, strawberries, kiwi, cabbage, green vegetables, rapeseed, mushrooms, seaweed, kelp, etc.

　　3. It is advisable to eat amaranth, cabbage, rapeseed, taro, kelp, seaweed, chicken blood, snake meat, pangolin, etc. for itching.

　　4. Prefer cooling blood and detoxifying foods. Such as: mung beans, glutinous rice, cucumbers, bitter melon, portulaca, green tea, etc.

　　Three, the best diet for vulvar contact dermatitis is to avoid eating those foods

　　1. Avoid foods that cause heat. For example: fish, shrimp, crab, chicken heads, pork heads, goose meat, chicken wings, chicken feet, etc., as eating them will exacerbate the itching and inflammation in the private parts.

　　Try to eat less spicy and stimulating foods. For example: onions, pepper, chili, Sichuan pepper, rapeseed, fennel, etc.

　　Avoid eating fried and greasy foods such as fried dough sticks, butter, butter, chocolate, etc., as these foods have the effect of promoting dampness and increasing heat, which will increase the secretion of leukorrhea and is not conducive to the treatment of the disease.

　　4. Quit smoking and drinking. Smoking and drinking are very irritating and can exacerbate inflammation.

　　First, traditional Chinese medicine treatment methods for vulvar contact dermatitis

　　1. Simple formula

　　(1) Xu Changqing 500 grams, decoct twice a day, morning and evening, each time decocting 500 milliliters of water, steam and wash the affected area when warm.

　　(2) Chayang decoction Herba capparis 15 grams, Sophora flavescens 30 grams, Cynanchum wilfordii 15 grams, Paeonia lactiflora 15 grams, Shechuangzi 30 grams, Euphorbia fischeriana 15 grams, decoct water for sitting bath.

　　(3) Shechuangzi washing formula Shechuangzi 30 grams, Sichuan pepper 12 grams, white precipitate 30 grams, decoct water for sitting bath.

　　(4) Qingdai powder,

　　2. Other therapies:Sanyinjiao, Yinlingquan, Zusanli, Pishu (Daofa). Since vulvar eczema has exudation of water, the acupoints should be avoided at the eczema site

　　Second, Western medicine treatment methods for vulvar contact dermatitis

　　1. Acute Phase

　　For those with erosion and exudation, normal saline, 3% boric acid wet敷, 1% magnesium sulfate solution, green tea water, purslane decoction, etc. can be used for cold compress. For acute dermatitis with redness, swelling, blisters, and little exudation, zinc oxide oil and corticosteroid ointment can be used. For secondary infection, 0.1% escharicin (Rivanol) solution, 1:5000 potassium permanganate solution can be used for wet敷, and then external application of a mixture containing hormones, antibacterial, and antifungal preparations such as nystatin/sulfate neomycin/short-chain actinomycin/trental (Compound Kangle cream), triamcinolone acetonide/miconazole/neomycin (Picon cream), triamcinolone acetonide (Paierisong) and others. For subacute stage, various corticosteroid ointments can be used. For chronic dry, thickened damage, moisturizing corticosteroid cream or ointment preparations rich in water can be used. For light red spots with only dryness or mild desquamation, a single protective ointment such as silicone ointment can be used. For those without erosion and exudation, calamine lotion can be applied after wet敷. For chronic eczematous dermatitis, topical corticosteroid ointment can be used.

　　2. Oral Medication

　　Antihistamines with anti-allergic and antipruritic effects such as chlorphenamine tablets (Pyrilamine), cimetidine tablets, hydroxyzine (Atarax) of the first generation, or the new generation of cetirizine (Zyrtec), loratadine (Clarityn), mizolastine (Mizolastine) and others can be taken as needed, 1-2 types. For severe and widespread acute contact dermatitis, systemic corticosteroid hormones should be used, and the dose is determined according to the condition.