Hidden hair disease rarely shows symptoms until infection occurs in the sinus tract. Typically, there are tiny pits in the caudal midline without any sensation. The pits have tiny holes, some of which are difficult to access with a lacrimal sac probe. So, how should a patient be diagnosed who presents with a small pit in the midline of the tail without any sensation? Here is a brief description: The disease is rarely symptomatic until infection of the sinus tract occurs. The typical case is a small pit in the midline of the tail without any sensation. The pit has a fine hole, which in some cases is difficult to access with a tear sac probe. This is the primary sinus tract, 5 to 6 cm from the anus. superficial abscesses form locally after infection and discharge pus after self-rupture or surgical incision. The abscess discharges thin pus for a few days and then gradually heals, leaving a hard node. Another abscess may appear after another bacterial infection. The above symptoms are repeated. This is repeated so that several sinus openings can develop locally. These sinus openings may be very close together or may be 2 to 3 cm apart. Most of the sinus openings allow for the passage of a fine probe. The sinus tracts vary in depth and can be up to several centimeters deep. The secondary sinus tracts are mostly above the primary sinus opening, i.e., on the cranial side. It is observed that they are often slightly to one side, especially to the left. In the dry phase of the sinus tract area a long oval hard nodule or cystic mass can be palpated here.