Aerosinusitis, also called barosinusitis, sinus squeeze or sinus barotrauma is a painful inflammation and sometimes bleeding of the membrane of the paranasal sinus cavities, normally the frontal sinus. It is caused by a difference in air pressures inside and outside the cavities. Presentation
Typically, sinus barotrauma is preceded by an upper respiratory tract infection or allergy. The affected person has a sudden sharp facial pain or headache during descent, which increases as the aircraft approaches ground level. The pain can ultimately become disabling unless the ambient pressure is reversed. The pressure difference causes the mucosal lining of the sinuses to become swollen and submucosal bleeding follows with further difficulties ventilating the sinus, especially if the orifices are involved. Ultimately fluid or blood will fill the space. In most cases of sinus barotrauma, localized pain to the frontal area is the predominant symptom. This is due to pain originating from the frontal sinus, it being above the brow bones. Less common is pain referred to the temporal, occipital, or retrobulbar region. Epistaxis or serosanguineous secretion from the nose may occur. Neurological symptoms may affect the adjacent fifth cranial nerve and especially the infraorbital nerve. Pathology
The pathology of sinus barotrauma is directly related to Boyles law, which states that the volume of a gas is inversely proportional to the pressure on it, when temperature is constant (P1 × V1 = P2 × V2). Two types of acute barotrauma are observed: squeeze and reverse squeeze.
Agoraphobia without a history of panic disorder (also called primary agoraphobia) is an anxiety disorder where the individual with the diagnosis does not meet the DSM-5 criteria for panic disorder. Agoraphobia typically develops as a result of having panic disorder. In a small minority of cases, however, agoraphobia can develop by itself without being triggered by the onset of panic attacks. Agoraphobia can be caused by traumatic experiences, such as bullying or abuse. Historically, there has been debate over whether agoraphobia without panic genuinely existed, or whether it was simply a manifestation of other disorders such as panic disorder, generalized anxiety disorder, avoidant personality disorder and social phobia. One researcher said: "out of 41 agoraphobics seen (at a clinic) during a period of 1 year, only 1 fit the diagnosis of agoraphobia without panic attacks, and even this particular classification was questionable...Do not expect to see too many agoraphobics without panic". In spite of this earlier skepticism, current thinking is that agoraphobia without panic disorder is indeed a valid, unique illness which has gone largely unnoticed, since those with the condition are far less likely to seek clinical treatment. Diagnostic criteria (DSM-IV-TR)
According to the DSM-IV-TR, a widely used manual for diagnosing mental disorders, the condition is diagnosed when agoraphobia is present without panic disorder where symptoms are not caused by or are unreasonable to an underlying medical problem or pharmacological influence. See also
Panic disorder
Agoraphobia

References
Spiti Raffaello, Scarpato Maria Alessandra, Spiti Alessandra (2011). "Primary agoraphobia specific symptoms: from natural information to mental representations".