Crow’s eye, light thorn Medical: ClavusKlavus
A cornea is a growth of the cornea (hyperkeratosis). This is usually round and between 5 and 10 millimeters in size. In its center there is a mostly yellowish translucent horny wedge (which represents the “eye”), the tip of which is directed into the depth and which can cause pain by exerting pressure on the deeper lying tissue.
The deeper this spur is, the more painful the corn usually is. The formation of calluses is caused by the fact that the corresponding part of the body tries to protect itself better from external influences by a thicker, harder skin. The most common trigger is chronic pressure or friction, especially on skin close to the bone.
In principle, corns can develop on any part of the body, but feet or toes are a preferred location. On the sole of the foot (so-called plantar clavi) they usually develop near the heads of the metatarsals. On the toes, corns are often found near the toe joints (dorsal or digital clavi).
As a rule, corns do not pose any further health risk and are therefore usually only treated if there is an increased risk of complications developing or if they cause a pronounced feeling of discomfort in the patient. Because the thickening of the cornea is often very similar to a bird’s eye, this change has been known since the 16th century under the name corn or crow’s eye. The name light thorn comes from the fact that it is a dead tissue.
Women suffer slightly more frequently from corns than men. This is because they tend to wear unsuitable footwear and thus expose their feet and toes to unnecessary strain. In addition, patients with diabetes mellitus or circulatory problems have an increased risk of developing corns.
The basis for the development of a corn eye is the persistent friction or chronic pressure on a certain part of the body. The stronger and longer these factors persist, the more likely they are to lead to cornification. This is due to the fact that certain cells of the outermost skin layer of the epidermis (so-called corneocytes) form an increased number of corneas at the affected area to protect themselves from the additional pressure.
The most common causes of such pressure are incorrect, i.e. usually too tight, footwear, malpositioning of feet or toes or protruding bones or joints. Other orthopedic peculiarities such as arthrotically changed joints or peculiarities such as a flat or splay foot can further promote the development of a corn. In addition, a virtually infinite number of other factors are potential triggers, such as some sports, the (regular, long-lasting) playing of a musical instrument or game console and so on.
A corn eye on the middle finger, for example, can simply be caused by writing a lot and therefore exposing a certain part of the finger to the pressure of the writing instrument for a long period of time. Especially between the toes, poor ventilation and/or insufficient drying can also lead to soft corn. These are often particularly painful.
In rare cases, callus formation occurs even without the area being exposed to increased friction or pressure. Then it is possible that the hyperkeratosis was caused by another disease (for example by syphilis or leprosy), is the result of poisoning (for example by arsenic) or is due to a viral infection. As a rule, i.e. an uncomplicated cornification without complications, the only symptom is often the cosmetic change of a specific, well defined region of the skin.
However, this is often accompanied by more or less severe pain. This can be explained by the fact that the central horny wedge penetrates deeper and deeper layers of skin over time and eventually meets and irritates free nerve endings, which is perceived as painful. Due to the pain, the patient may find it difficult or even impossible to walk and may be more or less restricted in several everyday activities, always depending on the location of the cornea.A prolonged irritation can lead to inflammatory reactions against the horn wedge, which impresses with the typical defensive reactions to foreign bodies, including the symptoms of redness and pus formation.
In diabetics or in people who suffer from neuropathy for other reasons, the sensation of pain is attenuated, which at first sight seems to be practical, since pain that develops is much weaker or even not noticed at all. However, since a corn may not be noticed until very late, for example when it is already in a very advanced stage, it can cause more serious changes, such as the development of a fistula or ulcer. Sometimes, problems can also arise due to accumulating infections, which can eventually result in diabetic gangrene (burn).
Corns often occur between the toes. The reason for this is that the space between the toes is very narrow. This causes the toes to rub against each other again and again.
It varies from person to person how much the friction on the toes is. In the ideal case, there is virtually no friction between the toes. Malpositioning of the toes often results in permanent pressure points.
At these pressure points, corns are the most common cause. But also a general foot malposition can cause unnatural friction between the toes. If once a corn has developed in the inter-toe area, then symptomatic, but also the cause must be treated.
The removal of the existing corn can be done with creams, tinctures and special plasters. As the area between the toes is difficult to treat, it should be considered to use professional foot care. Especially between the toes corns can be very painful.
