A 9-year-old girl has been suffering from gingival hemorrhages, cracks in the mouth angles for a month. She has a history of frequent nosebleeds, rapid fatigability. Objectively: the skin of the face and oral mucosa are pale. In the mouth angles there are cracks reaching the red border. Gingiva in the region of the 11 and 12 teeth is hyperemic and edematous, bleeds when touched.DMF/dmf = 10. Back of the tongue is bright red, smooth, glossy. Submandibular lymph nodes are slightly enlarged, mobile, painless. What specialist should be consulted in the first place?