What is acne?
Acne, also known as acne vulgaris or common acne, refers to an excessive production of oil by the sebaceous glands, which leads to an expansion or inflammation of the hair follicles .
Acne usually appears in adolescents as red spots on the face, neck or shoulders . In severe cases, acne can also appear on the back and chest. Sometimes, acne develops in infants and adults.
This article includes definitions and images of different types of acne. In a separate article, there is a detailed description of symptoms, causes, risk factors, prevention and treatment of acne.
Types of Acne
Acne can be divided into different types according to :
- The form: open comedones (blackheads), closed comedones (whiteheads), papules (flat red bumps), pustules (red bumps with pus in the center), nodules and cysts
- The severity:
- Mild acne: less than 30 lesions limited to open and closed comedones, papules and pustules
- Moderate acne: 30-125 lesions, which include papules and pustules
- Severe acne: >125 lesions or the presence of severe forms of acne, such as nodular or cystic acne, acne conglobata or fulminans
- The life period in which acne appear: neonatal (in newborns), infantile (in infants) and adult acne (after age of 25)
- Underlying cause:
- Mechanical acne due to physical irritation of the skin
- Hormonal acne in certain hormonal disorders
- Steroid acne as a side effect of steroid drugs
Mild Acne: Whiteheads and Blackheads
Whiteheads and blackheads are noninflamed acne; they are the hair follicles clogged with oil. In whiteheads or closed comedones, the openings of the hair follicles are covered by a thin skin layer (Picture 2). In blackheads or open comedones, the oil at the top of the hair follicles is in direct contact with air, so it oxidizes and turns black (Picture 3).
Mild to Moderate Acne: Papules and Pustules
Papules and pustules are inflamed acne. Papules are flat red bumps (Picture 4). Pustules are red bumps with white centers, which contain pus (Picture 5).
Adult acne is acne (usually papules and pustules) that appears after age of 25, mainly in women (Picture 6) .
Neonatal and Infantile Acne
Neonatal acne appears in newborns (Picture 7) and infantile acne in infants, mainly in boys (Picture 8) .
Hormonal acne is usually severe acne that develops in certain hormonal disorders, such as Cushing’s disease, or as a side effect of steroid drugs, including oral corticosteroids, steroid creams, oral contraceptives and anabolic steroids (Pictures 9 and 10).
Severe Acne: Nodular and Cystic Acne
Nodular acne is big, red and hard acne with inflammation deep in the skin (Picture 11). Cystic acne is similar to nodular acne but the red bumps are filled with pus, so they are soft (Picture 12).
Very Severe Acne: Acne Conglobata and Fulminans
Acne conglobata is a globe-forming type of acne that develops by the accumulation of several individual acne (Picture 13). Acne fulminans, which means “sudden, like lightning,” is a very severe and painful or bleeding acne, which can develop on the chest or back, mainly in young males (Picture 14).
Other conditions called acne that are not true acne:
- Acne rosacea = rosacea – red rash on the cheeks and nose
- Acne necrotica or “scalp acne” = a rare type of folliculitis on the scalp
- Chloracne = skin inflammation caused by poisoning, for example, by chlorinated dioxins