Can You Get Hemophilia A Later in Life? What to Know

Yes, it is possible to develop a form of hemophilia later in life, even if you were not born with it. While classic congenital Hemophilia A is a genetic condition you inherit, there is a rare, distinct condition called Acquired Hemophilia A (AHA) ^[1][2].

Acquired Hemophilia A is an autoimmune disorder. This means your immune system mistakenly produces antibodies (called inhibitors) that attack and neutralize your body’s own clotting factor VIII ^[1]. Because your factor VIII no longer works normally, your blood loses its ability to clot properly, leading to unexpected and often severe bleeding ^[3].

When to Seek Immediate Emergency Care

Because Acquired Hemophilia A can cause life-threatening internal bleeding, it is considered a medical emergency ^[4]. Do not wait to see if symptoms improve. Seek immediate emergency medical care if you experience:

• Rapidly enlarging, painful bruises or hematomas (firm pools of blood under the skin)
• Blood in your urine or stool (including black, tarry stools)
• Vomiting or coughing up blood
• Severe headache, confusion, or severe weakness
• Sudden, severe back or abdominal pain
• Shortness of breath
• Any bleeding that will not stop

Important precautions: While awaiting or undergoing treatment, do not take aspirin, ibuprofen, naproxen, or other NSAIDs unless specifically instructed by your hematologist, as these increase bleeding risk. Avoid intramuscular injections, tell all healthcare providers and dentists about your condition, and consider wearing a medical alert bracelet.

How Acquired Hemophilia A Differs from Classic Hemophilia

Although both conditions involve a shortage of factor VIII, they affect different people and present differently:

• Who gets it: Genetic hemophilia A is present from birth, though mild cases are sometimes only discovered later in life after surgery or trauma ^[5]. Acquired hemophilia A affects men and women equally, and typically appears in older adults ^[6]. It can also develop in younger women during pregnancy or, more commonly, one to four months after childbirth ^[7].
• Underlying associations: About half of acquired hemophilia cases happen for no known reason (idiopathic) ^[8][9]. The other half are associated with underlying health conditions, such as other autoimmune diseases, pregnancy, or certain cancers ^[10][9]. Finding an association does not automatically mean you have cancer; your doctor will use your history and age-appropriate screenings to guide the evaluation.
• Bleeding patterns: Moderate or severe genetic hemophilia A frequently causes deep bleeding inside the joints, such as the knees or elbows ^[11][12]. In contrast, acquired hemophilia A typically causes sudden, severe bleeding into the skin (producing massive bruises), muscles, or mucous membranes ^[13][14][12].

How is it Diagnosed?

Acquired Hemophilia A is usually suspected when someone with no personal or family history of bleeding problems suddenly develops large, unexplained bruises or severe bleeding ^[13][14].

A routine blood test may show an isolated prolonged aPTT (a measure of how long it takes blood to clot) ^[4][15]. A prolonged aPTT is just a clue, not a confirmation. To officially diagnose AHA and rule out other issues (like medication side effects or previously unrecognized mild genetic hemophilia), doctors will run specific blood tests. These include checking your actual factor VIII activity levels, performing a “mixing study,” and running an inhibitor assay (such as the Bethesda test) to confirm the presence of the autoimmune antibodies ^[16][17].

How is it Treated?

Treatment requires specialized care from a hematologist and focuses on two main goals:

1. Stopping the bleeding
Standard human factor VIII replacement therapies are often quickly neutralized by the body’s antibodies. Instead, doctors typically use specialized medications to stop active bleeds ^[4][16]. These may include bypassing agents (medicines that activate clotting downstream of factor VIII) or recombinant porcine factor VIII (a laboratory-produced medicine based on the pig factor VIII sequence) ^[4][16][18]. The choice depends on your specific inhibitor levels, bleeding severity, and clotting risks.

2. Eradicating the inhibitor
To induce remission, doctors use immune-suppressing medications to stop your immune system from attacking factor VIII ^[16][4]. These medications—which may include corticosteroids, rituximab, or cyclophosphamide—are highly individualized based on your age, overall health, and inhibitor levels ^[16]. Because immune suppression carries significant risks, such as serious infections or changes in blood counts, you will be monitored closely ^[19].

Once the bleeding stops and the inhibitors are eradicated, you will need ongoing laboratory surveillance ^[16]. Doctors will regularly monitor your factor VIII and inhibitor levels because relapses can occur. A recent review recommends maintaining this surveillance for at least two years after complete remission, though the exact schedule will be tailored to you ^[16].