Characterized by multiple round or oval purple papules measuring less than 0.5 cm in diameter, hereditary hemorrhagic telangiectasia (HHT) is a genetically transmitted disease, inherited as an autosomal dominant trait(Figure 6-3). The lesions represent multiple microaneurysms, owing to a weakening defect in the adventitial coat of venules. The lesions are so distinct as to be pathognomonic. There may be more than 100 such purple papules on the vermilion and mucosal surfaces of the lips as well as on the tongue and buccal mucosa. The facial skin and neck are also involved. Examination of the
nasal mucosa will reveal similar lesions, and a past history of epistaxis may be a complaint. Indeed, deaths have been reported in HHT attributable to epistaxis. The lesions may be seen during infancy but are usually more prominent in adults.
Although the differential diagnosis should include petechial hemorrhages with an attending platelet disorder, petechiae are macular rather than papular and (as foci of erythrocyte extravasation with breakdown to hemosiderin) red or brown rather than purple. Furthermore, HHT is genetic and should have been noticed in other family members. If any doubt exists, platelet studies can be ordered to rule out a blood dyscrasia.
Microscopically, HHT shows numerous dilated vascular channels with some degree of erythrocyte extravasation around the dilated vessels.
There is no treatment for the disease. If the patient would like to have the telangiectatic areas removed for cosmetic reasons, the papules can be cauterized by electrocautery in a staged series of procedures using local anesthesia.