The auricle forms with the external auditory canal the so-called outer ear. The two structures of the outer ear serve to absorb sound (pinna) and transmit it (external auditory canal) to the inner eardrum. To fulfill these functions, nature has provided for a direct connection between the pinna and the external auditory canal. This is important because inflammations that supposedly affect the visible auricle often have their true origin in the area of the non-visible auditory canal. However, an inflammation limited to the auricle can also occur.
Causes
In principle, infectious and non-infectious causes of auricular inflammation can be distinguished. Infectious inflammation can be triggered by bacteria, viruses or fungi, which usually infect the ear canal and can then also make themselves felt on the auricle. Such infections are promoted by factors that act on the body from outside as well as by the body’s own.
Examples of external factors include bathing in unclean water and minor injuries when cleaning the ear canal. The body’s own factors include bony protrusions in the area of the auditory canal and accumulations of earwax (cerumen). These factors can hinder the self-cleaning of the ear and thus form the basis for the growth of various pathogens, which can then cause an inflammation of the auditory canal and the auricle.
Persistent inflammation of the middle ear can also be a cause, as pathogens from the middle ear can also reach the outer ear. However, especially if the skin of the pinna is already damaged, pathogens can also penetrate directly into the pinna and cause a localized infection without involving the ear canal. The inflammation is often limited to the cartilage of the auricle and is then referred to as perichondritis.
The cause of an inflammation that also affects the earlobe is often bacterial in nature. Since the earlobe, unlike the auricle, has no cartilage, this is a skin infection, the so-called erysipelas. In addition, chickenpox viruses can cause an inflammation in the area of the auricle.
The infection can occur again if the patient has not yet had chickenpox or if there is no sufficient defence against the viruses. However, it is also possible that reactivation, i.e. activation of viruses that were previously in a dormant state, occurs. These viruses remain in the body after the patient has had chickenpox and can lead to new symptoms, especially if the immune system is weak.
The resulting disease is then called shingles (zoster). The shingles of the ear is called Zoster oticus. Contact eczema is the main non-infectious cause.
This type of inflammation can be caused by an allergic reaction, i.e. a hypersensitivity reaction. Triggers can be substances that have direct contact with the auricle or the auditory canal. These can be contained, for example, in jewelry or earplugs, but also in medicines (for example, ear drops).
In addition, products such as shampoo and other hair care products, as well as cosmetics should also be considered. On the other hand, a so-called toxic reaction is also conceivable. In this case, in contrast to an allergic reaction, no harmless substances act on the skin, but contact is made with harmful substances that directly attack the skin and thus cause inflammation.
However, the aforementioned inflammation of the cartilage of the auricle, perichondritis, can also be caused not only by infectious pathogens, but also by non-infectious factors such as exposure to sunlight, heat or cold. Finally, it should be mentioned that an inflammation of the auricle can also be an expression of an underlying skin disease. For example, psoriasis or atopic eczema (neurodermatitis) can also be behind it.
