Summary about Disease
Aquagenic urticaria is a rare type of physical urticaria, a skin condition characterized by hives (itchy welts) that develop rapidly after contact with water, regardless of its temperature. It is not an allergy to water itself but rather a reaction to something in the water or to the interaction of water with the skin. It is much more common in women.
Symptoms
The primary symptom is the development of small, itchy welts (hives) on the skin within minutes of water exposure. These hives are typically 1-3 mm in diameter. The welts are usually surrounded by redness (erythema). Symptoms often appear on the neck, chest, and back, but can occur anywhere on the body. Intense itching and burning sensations are common. In severe cases, individuals may experience systemic symptoms like difficulty breathing or swallowing, wheezing, and throat swelling (rare).
Causes
The exact cause of aquagenic urticaria is not fully understood. It is believed that water interacts with a substance on the skin, triggering an immune response. Some theories propose that it may involve an antigen (allergy-causing substance) dissolving in water and penetrating the skin. Some research suggests involvement of the degranulation of mast cells that release histamine and cause the hives. Genetic factors might also play a role in predisposing individuals to this condition.
Medicine Used
Treatment focuses on managing symptoms.
Antihistamines: These are the primary treatment, helping to block the histamine release that causes itching and hives. Both H1 and H2 antihistamines may be used.
Topical Creams/Ointments: Emollients and barrier creams may provide a protective layer on the skin.
UVB Light Therapy: In some cases, exposure to UVB light may help to desensitize the skin.
Omalizumab: An injectable monoclonal antibody that targets IgE, has shown promise in some severe cases.
Epinephrine: Should systemic reactions develop (e.g., difficulty breathing), epinephrine may be necessary.
Oral Corticosteroids: May be used for short-term relief of severe symptoms.
Is Communicable
No, aquagenic urticaria is not communicable or contagious. It is not an infection and cannot be spread from person to person.
Precautions
Minimize Water Exposure: Limit showers, baths, and swimming.
Use Lukewarm or Cool Water: Hot water may worsen symptoms.
Pat Skin Dry: Avoid rubbing the skin after water exposure.
Barrier Creams: Apply a protective barrier cream or emollient before exposure to water.
Avoid Activities That Induce Sweating: Sweating can trigger symptoms in some individuals.
Monitor for Severe Reactions: Be aware of potential systemic symptoms and seek immediate medical attention if they occur.
Water Softeners: Consider using water softeners to reduce mineral content in water.
How long does an outbreak last?
Individual hives typically resolve within 30-60 minutes after water exposure ceases. However, new hives can continue to appear as long as the skin is in contact with water. The overall duration of symptoms depends on the length of water exposure.
How is it diagnosed?
Diagnosis is primarily based on a detailed medical history and a physical examination. A water challenge test is often performed, where a small amount of water is applied to the skin, and the area is observed for the development of hives. Allergy testing is usually negative, as it's not a true allergy.
Timeline of Symptoms
Within Minutes of Exposure: Itching and redness (erythema) begin.
5-15 Minutes: Small, distinct hives (welts) develop.
30-60 Minutes After Exposure Ceases: Hives typically start to fade and resolve.
Prolonged Exposure: New hives may continue to appear as long as the skin is in contact with water.
Important Considerations
Psychological Impact: Aquagenic urticaria can significantly impact quality of life due to the constant need to avoid water.
Differential Diagnosis: It's important to rule out other types of urticaria and skin conditions.
Individual Variability: The severity of symptoms and triggers can vary greatly between individuals.
Consultation with a Specialist: A dermatologist or allergist/immunologist with experience in urticaria is essential for proper diagnosis and management.
Rare Condition: Aquagenic urticaria is very rare; many healthcare professionals may not be familiar with it.