Hereditary Angioedema (HAE)
Hereditary Angioedema, or HAE for short, is a rare and often misunderstood condition characterized by recurrent swelling of the skin, mucous membranes of the gastrointestinal tract, and airways. These episodes can last between three and five days and often appear asymmetrically. The extremities, face, and external genitalia are particularly affected in cases of HAE.
Interestingly, these swellings do not occur alongside typical skin reactions such as urticaria (hives) or pruritus (itching). However, some patients report prodromal symptoms before an attack, such as a burning sensation on the skin, visible skin changes (erythema, skin lesions, flank erythema), numbness, or tingling sensations (paresthesia).
In cases where HAE affects the abdominal organs, severe pain can occur, often accompanied by nausea or vomiting. These symptoms are frequently caused by blockages in the gastrointestinal tract. Swelling in the throat and larynx area is especially dangerous, as it can lead to difficulty swallowing, shortness of breath, and in the worst cases, suffocation if immediate medical attention is not provided.
Causes of Hereditary Angioedema
HAE is caused by a deficiency or dysfunction of the C1 inhibitor (C1-INH) protein, which plays a crucial role in regulating inflammation and vascular permeability. The condition is inherited in an autosomal dominant manner, meaning that an affected parent has a 50% chance of passing it on to their children. However, in some cases, HAE can also arise due to spontaneous genetic mutations.
Diagnosis and Treatment
Because HAE is a rare condition, it is often misdiagnosed as an allergic reaction or another swelling disorder. Blood tests measuring C1-INH levels and function, as well as C4 complement levels, are essential for accurate diagnosis.
Although there is no cure for HAE, modern treatments help manage and prevent attacks. Therapies include C1-INH replacement therapy, bradykinin receptor antagonists, and kallikrein inhibitors, which help reduce swelling episodes and improve patients’ quality of life.