A skin rash that comes on after handling or eating shellfish may indicate a serious food allergy. Patients who don't suspect other known triggers for contact dermatitis, a group of allergy symptoms that affect the skin, should consider being tested for shellfish allergies. Echinoderms such as sea urchins, mollusks such as oysters and crustaceans such as shrimp may cause allergic reactions. Among shellfish, however, the crustaceans shrimp, lobster and crab generate the most allergic illness in Americans, according to the Food Allergy and Anaphylaxis Network, or FAAN.
Features
The symptoms of allergic contact dermatitis include skin irritation and redness, warmth and itching. Patches of skin may erupt in hives, or raised bumps, or may form fluid-filled blisters.
The University of Maryland Medical Center relates that these allergy symptoms can appear immediately after touching shellfish or up to two days later. Shellfish allergies occur in both adults and children.
Significance
People whose allergy symptoms are limited to the skin can still experience a wider range of health problems at any time. FAAN reports that handling and cooking shellfish enables its protein allergens to become airborne and inhaled, which can intensify the body's response. Additional health effects include runny and stuffy nose, mouth itching and swelling, digestive upset and rare episodes of anaphylaxis, a full-body allergic reaction.
Warning
In people with shellfish allergies, any contact with the microscopic allergens can initiate anaphylaxis, although the condition occurs less often from skin contact than from inhalation or ingestion. The National Institutes of Health advises an immediate call to 911 if patients develop additional allergy symptoms of abnormal pulse, weakness or trouble breathing. Anaphylaxis can swiftly escalate to loss of consciousness, respiratory arrest, coma and death.
Considerations
While allergies in children can come and go, shellfish allergies usually remain for life, the Mayo Clinic reports. Permanent food allergies can't be cured or even alleviated with immunotherapy shots, placing patients with shellfish sensitivities at continual risk for serious anaphylactic allergic reactions.
Identification
People can get skin rashes from substances unrelated to shellfish, such as other foods or household cleansers. Seeing a doctor for a diagnosis can identify a potentially serious problem with shellfish or rule out an allergic reaction. The Mayo Clinic notes that a skin test, blood test or special diet may reveal the need for patients to remove shellfish and other fish from their menus in order to stay healthy.
Solution
Although the rash will begin to fade when shellfish contact ceases and allergens pass from the body, stubborn rashes can linger. The UM Medical Center recommends topical medications and creams to ease skin irritation. Commercial preparations of corticosteroid cream and calamine lotion will treat inflammation and itching.
