**4. Diagnosis**

**3. Special types of contact urticaria**

• Stage 4: Anaphylactic and anaphylactoid reaction

54 A Comprehensive Review of Urticaria and Angioedema

**Table 4.** Contact urticaria syndrome staging [9].

Skin diseases are the second most common occupational diseases in Europe and occupational contact urticaria (OCU) makes up 1–8% of occupational skin disorders [12]. The most commonly affected professional groups are healthcare employees, food handlers, farmers and hairdressers [24, 25]. Immunologic and non-immunologic contact urticaria types can be seen in OCU. The risk of sensitization against all proteins is high in presence of atopy in OCU [10].

Natural rubber latex is the most commonly identified allergen and this allergy is seen in 1–3% in general population and 5–10% of healthcare workers in Europe [10]. *H. brasiliensis* proteins are the main responsible agents for natural rubber latex allergy [10]. A reaction against modified proteins (wheat, soy and Croetin Q) that are added to shampoo and especially ammonium persulfate is often observed in hairdressers [26, 27]. Reactions against saliva, amniotic fluid, urine and seminal fluid of animals have been defined in animal handlers, farmers and veterinarians. Dyes cause contact urticaria at significant levels in the cosmetic and industrial

"Oral allergy syndrome" is used to identify ICU developing in the mucosa [28]. It is characterized by mucosal edema, itching and a burning sensation after contact of the oral mucosa with respiratory allergens [29]. Cross-reactivity between homologous pollen and food allergens is accused in the etiology [29]. The term pollen-food allergy syndrome (PFAS) can therefore also be used [30]. Fruits and vegetables especially apples, carrots, tomatoes, pears, cherries, plums, celery, spices and hazelnuts are the agents that are often blamed for the oral allergy syndrome. The individuals who have oral allergy syndrome frequently suffer from atopy and pollen allergy,

Some physical urticaria cases occur following skin contact with hot, cold, light (UV: solar urticaria), water or as dermographism, pressure hives and vibratory angioedema. A physical

Besides, atopy is also important in OCU associated with NICU [10].

• Stage 1: Localized urticaria, dermatitis, nonspecific symptoms (itching, tingling, burning, etc.)

• Stage 3: Bronchial asthma, rhinoconjunctivitis, orolaryngeal symptom and gastointestinal dysfunction

therefore a cross allergy against IgE antibodies has been observed [30].

**3.2. Oral allergy syndrome (food contact dermatitis)**

**3.1. Occupational contact urticaria**

• Stage 2: Generalize urticaria

sectors [4, 6].

**3.3. Physical contact urticaria**

The contact urticaria diagnosis is made with a detailed history and dermatologic examination. The detailed history should include the occupation, hobbies, additional systemic disorders and current medication of the patient, and when the lesion started, how long it lasted and the presence of accompanying symptoms (allergic rhinitis, conjunctivitis, gastrointestinal symptoms and angioedema) [7]. An open test, patch test, prick test, scratch test and intradermal test are the test mainly used for diagnosis.

The allergens are properly prepared and applied to the skin of the inner surface of the forearm or back in the open test. The test is conducted both with cooked and uncooked samples of the foods. The evaluation of the contact urticaria response should be performed 45-60 minutes after the contact of allergen with the skin [13]. This duration can be extended to 1 hour if NICU is suspected. A positive response in contact urticaria consists of edema and/or erythema [6].

The test substances for the rubbing test are prepared as in the open test and are applied by rubbing with a finger or cotton swab 15–20 times to increase the absorption. Dermographism should be tested before the rubbing procedure and the test should not be performed with latex gloves. The evaluation is performed 15–20 minutes after the test substances are removed [13].

The short-term patch test can be used to prevent the contact urticarial factors from spreading or drying. In the closed test method, the patch test sites are opened after 20 minutes and the urticarial reaction evaluated [13].

The prick test demonstrates the presence of specific tissue IgE against the allergen. It is used in the diagnosis of immunologic contact urticaria [13]. Commercial antigens in 2–3 ml bottles are used for the test. The test can be conducted on the skin of the inner surface of the forearm or the back. The evaluation is performed 15–20 minutes after the contact of the allergen with the skin. However, the test should be finalized early in case of severe reaction development. The most important point during the test is to use a separate lancet for each allergen and to apply the allergens 2 cm away from each other [13].

After a superficial scratch of 5–10 mm is formed with the lancet, the test substance is applied to the scratch and evaluation is performed 5–20 minutes later [13].

In the closed scratch test, the test substance is applied similarly and then covered. The evaluation of the test is performed 20 minutes later [13].

It is possible to use histamine hydrochloride as a positive control and aqueous sodium hydroxide as a negative control for the prick and scratch tests.

The radioallergosorbent test (RAST) measures specific IgE in the serum. It can be used for the diagnosis of ICU and CUS and also detect cross-allergenicity [16].

If a strong early reaction is suspected, the first step should be specific IgE measurement and it should be followed by non-invasive skin tests (open test-rubbing test and close test) and invasive skin tests (prick test, scratch test and closed scratch test) at the final stage [13]. Besides specific IgE measurement, open test should be used first when a direct puncture test is risky in latex allergy. It should not be forgotten that latex can cause cross-react with fruits, vegetables and seafood, plants and pollen while latex allergy is evaluated [18–21].

It is necessary to discontinue H1 antihistamines for 1 week, H2 antihistamines for 1 day, steroids (if used for longer than 1 week) for 1–3 weeks and phototherapy for a couple of weeks before skin tests [13, 35]. The possibility of an anaphylactic reaction should be considered during skin tests. All skin tests should therefore be conducted in the special clinic where the proper and necessary equipment are available.

### **5. Prevention and treatment**

The first step in the treatment is to avoid and eliminate the allergen. Identification of the allergens is therefore the main step of the treatment [36].

The secretion of histamine and other mediators from mast cells should be prevented to decrease symptoms. The first treatment step consists of 2nd generation H1 antihistamines. The antihistamine dose can be increased if there is no benefit at first. In addition to oral antihistamines, systemic steroid treatment can also be used in severe cases. Conducting the treatment in units where resuscitation can be performed is appropriate for anaphylaxis and anaphylactic shock cases [6].
