Swelling is the buildup of lymphatic fluids in the lymphatic vessels. As lymphatic vessels lack muscles, they cannot purge swollen fluids inside of them. So fluid tends to stagnate instead. Swelling in the Capillary Array of the chest causes panic attacks. Swelling in the Capillary anywhere else contributes to feelings of anxiety. So, swelling is not just a symptom all of its own, it can generate other imbalances in the body. Swelling is a major contributor to pain. It can often be found with EM Inflammation. Therefore, it is helpful to treat both as a set.
Swelling is often caused by histio quisquiliae such as progesterone, estrogen, and histamine. Since these are often generated by pathogens, swelling is a common sign of an infection of one sort or another. If you identify swelling, then you should look for progesterone. If you find this, then there are several pathogens to consider such as Norovirus, Rotavirus, Rhinovirus, Propionibacterium Acne, and Hantavirus. Thus far, I have only associated Rhinovirus with estrogen histio, so if you identify estrogen histio then you should look for Rhinovirus and then also clear reverse T3 histio to help reduce hypothyroidism. Histamine histio can be a sign of Herpes. If you find Herpes, look for nerve inflammation, EM Shingles, and stress hormone tissue histio. Propionibacterium Acne produces both swelling as well as edema generating tremendous pressure in the tissue it infects. If you identify P. Acne then also follow the Edema Protocol, also clear Cortisol Array Histio and use the EM Tighten Tissue Treatment to tighten tissues that the cortisol loosened as the pressure built inside the infected tissue.
In other words, you can diagnose swelling as a way of identifying locations of the body that might have infections.
Other perspectives on this issues:
Swelling is a form of Water Qi excess that can develop in lymphatic vessels. Veins and lymphatic vessels are Pericardium angles and the energy of Pericardium is Yin Fire and Yin Water. Being Yin and containing Water Qi means that they have a propensity towards Water Qi excess or relative Water excess if the Fire Qi in the Pericardium angle becomes deficient.
As an aside, Swelling developing in the Capillary Array causes feelings of anxiety. In the chest, this same phenomenon causes panic attacks.