Contact Urticaria and Contact Urticaria Syndrome

Contact urticaria is an instant, but momentary, localized swelling and redness, which occurs on the skin after direct contact with an offending stimulus. Contact urticaria syndrome is caused by a variety of compounds, such as foods, preservatives, fragrances, plant and animal products, and metals. It is a subcategory of physical urticaria.

Contact urticaria should be distinguished from other allergic contact dermatitis where dermatitis reactions develop a long time (hours or even days) after contact with the offending stimulus.

The contact can be immunologic and nonimmunologic. Causes of nonimmunologic contact urticaria include balsam of Peru, benzoic acid, cinnamic alcohol, cinnamic aldehyde, sorbic acid, and dimethylsulfoxide. Causes of immunologic contact urticaria include natural rubber latex, raw meat and fish, semen, many antibiotics, some metals (e.g. platinum, nickel), acrylic monomers, short-chain alcohols, benzoic, and other miscellaneous chemicals.

Since the exposure to contact urticaria patients is usually similar to other contact stimulus, watchfulness is required to make certain that the patient is properly investigated and diagnosed with contact urticaria syndrome.

Contact urticaria can be characterized by itching, local burning sensation, and tingling; red swellings or wheals may also occur, especially on the hands. The color of the wheals shows the severity, which can range from slight redness or spots with minimal swelling to fiery redness with tense swelling and wheals. Rash caused by contact urticaria usually resolves by itself within 24 hours of onset.

The worst thing about contact urticaria is that symptoms may occur in organs other than the skin due to unknown triggers. They are more likely to occur in patients with immunological contact urticaria. Features of extracutaneous reactions that can be caused by contact urticaria syndrome include wheezing, runny nose, watery eyes, lip swelling, hoarse throat, difficulty swallowing, nausea, vomiting, diarrhea, cramps, and severe anaphylactic shock, which can be life threatening.