Average Age of Onset for Hereditary Hemorrhagic Telangiectasia (HHT)
The majority of HHT patients (62%) become symptomatic by age 16 years, with virtually all patients manifesting symptoms by age 40 years. 1
Age-Specific Manifestation Patterns
Childhood Onset (Most Common)
- Epistaxis (nosebleeds) is the earliest and most common presenting symptom, typically beginning in childhood with a mean age of onset around 11 years 2
- The earliest documented age of epistaxis onset in pediatric series is 4 years 3
- 90% of HHT patients experience epistaxis as their first symptom of disease 1
Progression Timeline by Manifestation Type
Mucocutaneous telangiectases appear 5 to 20 years after the onset of epistaxis, typically emerging in late adolescence or early adulthood 1
Visceral arteriovenous malformations (AVMs) demonstrate age-related penetrance patterns 4:
- Spinal cord AVMs present earliest (mean age 2.2 years) 4
- Cerebral AV fistulae occur predominantly before age 6 years (mean age 3.0 years) 4
- Nidus-type cerebral AVMs manifest later (mean age 23.1 years) 4
- Micro-AVMs appear in adulthood (mean age 31.8 years) 4
Gastrointestinal telangiectases typically present much later, with a mean age of 55.4 years 2
Critical Diagnostic Delay Issue
A major clinical problem is the substantial diagnostic delay—averaging 26.4 years from symptom onset to correct diagnosis 2. This occurs because:
- Early symptoms like childhood epistaxis are often attributed to common benign causes
- The full constellation of diagnostic features develops gradually over decades
- Patients seek care from multiple subspecialties without recognition of the underlying systemic disorder 2
Clinical Implications for Early Detection
Children from HHT families should undergo clinical examination and screening for occult visceral AVMs even when symptoms are discrete, as manifestations are detectable at earlier ages than historically recognized 3. The presence of recurrent epistaxis in a child with positive family history should prompt immediate evaluation for HHT, as early diagnosis prevents potentially devastating complications from undetected cerebral or pulmonary AVMs 3.