An atheroma is a benign skin cyst that develops when the duct of a sebaceous gland becomes blocked. Therefore the atheroma is also called sebaceous cyst. In the vernacular the term “groats bag” is also used.
The cyst is filled with sebum secretion and skin cells. It appears to be bulging elastic and bulges spherically like a 1 to 2 cm large bump above the skin level. It is often not painful and can occur anywhere on the body. In the centre of the swelling, the excretory duct of the congested sebaceous gland is often also visible as a black dot. The atheroma only needs to be removed if it becomes inflamed or causes discomfort.
Atheromas are bulging, elastic bumps that usually do not cause any complaints. Mostly they are perceived primarily as cosmetically disturbing. Sometimes, however, a feeling of tension of the skin may be perceived.
Most atheromas are about 1 to 2 cm in size. In some cases, however, the atheroma becomes as large as a hen’s egg. In this case the skin becomes very tense and stretched.
This can cause the hairs on the atheroma to be further apart than on other parts of the body. Sometimes the hairs in this area may be missing completely. An inflamed atheroma hurts. Also, when it is inflamed, it is no longer skin-colored, but reddened. In addition, it is overheated compared to the rest of the skin.
These are causes of atheroma
When it comes to the causes of an atheroma, one must distinguish between two causally different types of atheroma. The so called “real” atheroma is also called epidermal cyst and is optically conspicuous by a black spot in the centre of the swelling. This point represents the exit of the blocked excretory duct of a hair.
The exit point of the hair is blocked by skin cells in the epidermal cyst. This happens when the skin cells of the scalp multiply too quickly. As a result, skin cells accumulate in the excretory duct of the hair, since they can no longer be released to the surface of the skin as small horny scales.
The accumulation of the horny scales leads to the visible bump. If several atheromas occur simultaneously, this is often associated with acne. Atheromas can also develop after an injury to the skin. Furthermore, atheromas can also be a symptom of the rare Gardner syndrome. This is a hereditary disease, which is conspicuous not only by epidermal cysts but also by increased polyps in the intestine, benign bone tumours and soft tissue tumours.
Diagnosis of atheroma
The diagnosis of an atheroma can be made by a dermatologist. The dermatologist recognises the skin cyst by its characteristic appearance and its elastic consistency. Furthermore, atheromas are usually not painful.
The node only becomes painful when an inflammation is added. The differentiation between the epidermal cyst and the trichilemmal cyst, which are often both summarized under the term atheroma, succeeds on the one hand because the epidermal cyst has a central excretory duct, which the trichilemmal cyst does not have. In addition, the latter occurs mainly on the hairy head, whereas the epidermal cyst can occur on the whole body. They are mainly found on the face, the back, the upper arm and thighs and the scrotum.