Comedonal acne occurs when a hair follicle is blocked by sebum (a waxy skin oil) and dead skin cells. A single bump is referred to as a comedo, while multiple bumps are called comedones.
This article discusses what the different types of comedones look like and what causes them. It also covers how they’re diagnosed and how to treat or prevent them.
Comedonal Acne Symptoms
Comedonal acne doesn’t look like typical acne. In fact, many people with comedonal acne don’t consider themselves to have acne.
This is because comedones are not red or inflamed like a typical pimple. They don’t tend to swell to excessive proportions or have pus. Instead, they develop as smaller, non-inflamed bumps called papules that can either be closed or open.
Comedones are most common on the forehead, chin, and jawline. They can also develop on the face, neck, shoulders, back, or chest.
Symptoms can range from mild (with just a few odd blemishes) to severe (covering large areas of skin). Comedones can develop on their own or alongside acne vulgaris.
Types
There are several types of comedonal acne blemishes:
Closed Comedones
Closed comedones, commonly referred to as whiteheads, range in color from creamy white to flesh-toned. They occur when the oil plug develops well beneath the opening (pore) of the hair follicle. They appear most often on the forehead, chin, and cheeks.
Whiteheads are not painful. They cannot be “popped” since they do not contain pus or an underlying infection.
Open Comedones
Open comedones, or blackheads, occur when the oil plug is situated near the opening of a pore.
The dark color isn’t caused by dirt but rather a chemical reaction in melanin, the pigment responsible for the color of skin. When exposed to oxygen, the melanin in dead skin cells oxidizes and turns a dark-brown color, resulting in a blackhead.
If you were to extract a blackhead, you would see the top portion of the plug is dark. However, the lower portion remains a creamy white to yellow color.
Blackheads typically form on the sides and bridge of the nose as well as the chin, shoulders, and back.
Microcomedones
Microcomedones are the smallest of all acne blemishes. These comedones, invisible to the naked eye, are the “seeds” from which larger comedones emerge. Comedones and inflamed pimples begin their life as microcomedones.
Macrocomedones and Giant Comedones
Macrocomedones are either closed or open comedones that are larger than usual. They can range from one millimeter (0.04 inches) to three millimeters (0.12 inches) in diameter. Usually, a macrocomedo will be open since it will be large enough to push to the opening of a pore.
Giant comedones are blackheads that range in size from several millimeters to two centimeters (0.78 inches) in diameter. They typically occur as single blackheads and mainly affect older adults.
Solar Comedones
Solar comedones, also called senile comedones, are caused by excessive sun exposure over a long period of time. They may be small or large, open or closed.
Chronic exposure to ultraviolet (UV) radiation from the sun can cause the skin to thicken and papules to develop in swollen skin pores. This usually happens around the eyes and on the nose, cheeks, or forehead.
Solar comedones most often occur in people over 60. However, they can begin to develop as early as your 40s with extreme sun exposure.
Causes
Comedones are associated with the pilosebaceous unit, which includes a hair follicle and sebaceous gland. Sebaceous glands produce sebum, the waxy oil that coats, moisturizes, and protects the skin.
The pilosebaceous units are densely clustered on the face, neck, upper chest, shoulders, and back. Excess amounts of keratin (a protein in skin, nails, and hair) combined with sebum can plug the follicle pore’s opening.
Risk Factors
Like most types of acne, comedonal acne is especially common during the preteen and teen years. However, it can occur at nearly every age, including adulthood.
Comedonal acne can sometimes be a sign of acne vulgaris to come, especially when it appears during puberty. With that said, having comedones doesn’t necessarily mean you’ll get pimples. Other factors (including genetics) appear to contribute.
Puberty also can contribute as the increased production of androgens (male hormones) can put the sebaceous glands into overdrive. The same can occur prior to the onset of a woman’s period when hormone levels spike.
Comedonal acne can sometimes be caused or made worse by things you put on your face or skin. This includes oily skin care products or hair pomades. High humidity and air pollution can also contribute.
Diagnosis
Comedonal acne can usually be diagnosed by appearance alone. If it doesn’t improve with topical treatment on your skin, a healthcare provider may check to see if you have another condition. Examples of other conditions include:
Keratosis pilaris (a benign condition that causes acne-like bumps) Fibrofolliculoma (a benign, or non-harmful, tumor of a hair follicle) Sebaceous hyperplasia (the benign enlargement of the sebaceous gland) Basal cell carcinoma (a type of skin cancer)
Treatment
As with other forms of acne, comedonal breakouts aren’t caused by a lack of hygiene. Scrubbing or washing your face more frequently is unlikely to clear up an outbreak. As important as daily skincare is, it can’t cure or prevent comedonal acne on its own.
However, there are over-the-counter (OTC) and prescription medications that can help. These include:
Salicylic acid Benzoyl peroxide Differin (adapalene) Topical retinoids Azelaic acid
If your acne is mild, you may be able to treat it with a topical OTC drug. For more severe or persistent acne, see a dermatologist.
Whether you use an OTC or prescription product, it may take up to 12 weeks before you see any improvement. Stick with it even if there are no immediate changes.
Prevention
Minor comedone outbreaks can be prevented or minimized by adjusting the way you care for your skin. Here are a few simple tips that may help prevent pore blockage:
Wash only twice daily. Cleansing acne-prone skin more often can cause irritation and leave skin dried and inflamed. Inflamed skin is more vulnerable to infection, increasing the risk of acne pimples. Use non-comedogenic skin products. These are non-oily moisturizers, cleansers, and cosmetics designed to prevent pore blockage. Some are labeled non-comedogenic, while others advertise themselves as anti-acnegenic. Keep your makeup brushes and applicators clean. Sebum and dead skin cells can accumulate on bristles and pads. You can usually remove them with warm, soapy water. Rinse thoroughly and allow to air-dry. Remove your makeup before bedtime. Sleeping with makeup residue contributes to pore blockage. Use a fragrance-free, non-alcohol makeup remover to avoid irritation. Some are made with glycerin or aloe vera to help moisturize skin. Wash after strenuous activity. Don’t let perspiration and oil stay on your skin. Take a shower and immediately rehydrate with a light, oil-free moisturizer.
Summary
Comedonal acne happens when your hair follicle has an oily plug of sebum and dead skin cells. Closed comedones, or whiteheads, form underneath your pore opening. Open comedones, or blackheads, develop near the pore opening.
Comedones are especially common during the teenage years but they can happen at any age. Hormone changes can be a contributing factor. Oily skin care products and humidity can also make it worse.
Your doctor can help make a diagnosis and ensure that your bumps aren’t caused by another condition. They may suggest a topical medication, including salicylic acid or benzoyl peroxide. You can also help prevent comedones by using non-comedogenic skin products, removing make-up at night, and washing your face twice a day.
A Word From Verywell
Comedonal acne may not be as apparent or bothersome as other types of acne. However, you may still be concerned about it. That’s completely understandable and it’s best to get it under control while it’s still relatively mild.
In the end, you will want to treat your acne appropriately. Overtreatment can be just as bad for your skin as undertreatment.
If left untreated, comedonal acne can develop into a more severe breakout and become more difficult to manage. It may take time to realize the benefits of treatments. Be patient and speak with your healthcare provider or dermatologist if you have any questions or concerns.
