An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response.
Earrings are jewelry that can be worn on one's ears. Earrings are commonly worn with an earlobe piercing or another external part of the ear, or by some other means, such as stickers or clip-ons. Earrings have been worn across multiple civilizations and historic periods, often carrying a cultural significance.
Basophils are a type of white blood cell. Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. They are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They also produce compounds that coordinate immune responses, including histamine and serotonin that induce inflammation, and heparin that prevents blood clotting, although there are less than that found in mast cell granules. Mast cells were once thought to be basophils that migrated from the blood into their resident tissues, but they are now known to be different types of cells.
In vertebrates, an ear is the organ that enables hearing and body balance using the vestibular system. In humans, the ear is described as having three parts: the outer ear, the middle ear and the inner ear. The outer ear consists of the auricle and the ear canal. Since the outer ear is the only visible portion of the ear, the word "ear" often refers to the external part (auricle) alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ear canal is cleaned via earwax, which naturally migrates to the auricle.
Demodex is a genus of tiny mites that live in or near hair follicles of mammals. Around 65 species of Demodex are known. Two species live on humans: Demodex folliculorum and Demodex brevis, both frequently referred to as eyelash mites, alternatively face mites or skin mites.
An ear-piercing instrument is a device designed to pierce earlobes by driving a pointed starter stud through the lobe. Piercing guns are typically used for ear piercing in mall jewelry shops, beauty salons, pharmacies, and doctors' offices.
An epidermoid cyst or epidermal inclusion cyst is a benign cyst usually found on the skin. The cyst develops out of ectodermal tissue. Histologically, it is made of a thin layer of squamous epithelium.
Otoplasty is a procedure for correcting the deformities and defects of the auricle, whether these defects are congenital conditions or caused by trauma. Otoplastic surgeons may reshape, move, or augment the cartilaginous support framework of the auricle to correct these defects.
Stretching, in the context of body piercing, is the deliberate expansion of a healed piercing for the purpose of wearing certain types of jewelry. Ear piercings are the most commonly stretched piercings, with nasal septum piercings, tongue piercings and lip piercings/lip plates following close behind. While all piercings can be stretched to some degree, cartilage piercings are usually more difficult to stretch and more likely to form hypertrophic scars if stretched quickly. Dermal punching is generally the preferred method for accommodating larger jewelry in cartilage piercings.
Darwin's tubercle is a congenital ear condition which often presents as a thickening on the helix at the junction of the upper and middle thirds.
Tissue alpha-L-fucosidase is an enzyme that in humans is encoded by the FUCA1 gene.
The prostaglandin D2 receptor 1 (DP1), a G protein-coupled receptor encoded by the PTGDR gene (also termed PTGDR1), is primarily a receptor for prostaglandin D2 (PGD2). The receptor is a member of the prostaglandin receptors belonging to the subfamily A14 of rhodopsin-like receptors. Activation of DP1 by PGD2 or other cognate receptor ligands is associated with a variety of physiological and pathological responses in animal models.
Eosinophil cationic protein (ECP) also known as ribonuclease 3 is a basic protein located in the eosinophil primary matrix. In humans, the eosinophil cationic protein is encoded by the RNASE3 gene.
Follitropin subunit beta also known as follicle-stimulating hormone beta subunit (FSH-B) is a protein that in humans is encoded by the FSHB gene. Alternative splicing results in two transcript variants encoding the same protein.
High affinity immunoglobulin epsilon receptor subunit beta is a protein that in humans is encoded by the MS4A2 gene.
Frank's sign is a diagonal crease in the ear lobe extending from the tragus across the lobule to the rear edge of the auricle. The sign is named after Sanders T. Frank.
Perichondritis is inflammation of the perichondrium, a layer of connective tissue which surrounds cartilage. A common form, auricular perichondritis involves infection of the pinna due to infection of traumatic or surgical wound or the spread of inflammation into depth. It may lead to severe deformation of the pinna if not treated vigorously with IV antibiotics. The causative organism is usually Pseudomonas aeruginosa. A rare form is laryngeal perichondritis. It develops suddenly due to an injury, virulent organisms or compromised immune status of the host, and also affects cartilage of the larynx. This may result in deformations and stenoses.
Auricular hypertrichosis is a genetic condition expressed as long and strong hairs growing from the helix of the pinna.
Ear piercing is one of the oldest forms of body modification. It occurs when holes are created on the ear lobes or cartilage to allow the insertion of decorative ornaments, such as earrings. Ear piercing in children has been around for centuries as part of ritualistic and cultural traditions but has continued to become a worldwide mainstream fashion statement. It is extremely common in Nigeria, India, Brazil and Hispanic countries.
Metal allergies inflame the skin after it has been in contact with metal. They are a form of allergic contact dermatitis. They are becoming more common, as of 2021, except in areas with regulatory countermeasures.
