Overview

Nodular acne is a serious skin condition characterised by hard lumps under the skin called nodules, which only show as spots on the surface. Like regular acne, this is most prominent in the face and there are several factors that affect your chances of developing it. Nodular acne is caused by oil buildup under the skin, which in turn depends on various genetic and lifestyle factors such as diet, hormones and skincare habits.

What is nodular acne?

Acne is a common skin condition caused by blockages in hair follicles from oil and dead skin. The result is the presence of pimples and blackheads, but spots are the most common sign. It is normal for the skin to be oily. Acne usually shows on your face, but can also be present on the chest or back.

The severity of acne varies between people and with age (where it can persist into early adulthood). You may experience certain times where oiliness and spot frequency may be higher than others, and these are informally referred to as “breakouts”. Acne is common in teenagers due to the hormones that are released during puberty. The more these hormones are secreted, the more noticeable the effects are.

In more severe cases, nodular acne consists of hard bumps under the skin called nodules. This is due to an increased buildup of oils and the release of androgen hormones. The nodules are generally quite painful to touch and are likely to scar in the future if not treated properly.¹

Despite nodular acne being as common as 20% of all acne cases in the UK, knowing what factors are responsible can help you better understand how to minimise its severity.

Genetics

If you have a history of acne or other skin-related issues through your family tree, there is a chance that genes play a role in the condition. It is believed that two genes influence the predisposition of acne, IGF-1 and AR (androgen receptor) genes.² You can undergo genetic screening to check whether you have these genes at a level that may be considered “average”, which can either provide:

• Insight into whether you are more likely to develop acne (if you have not reached adolescence yet) 
• A potential explanation for acne you may have developed in the past (if you are currently in adulthood)

Androgen receptors are responsible for the development of male sexual characteristics including facial hair, which affects the properties of your skin in this region. Nodular acne is caused by an over-expression of AR genes, leading to a faster and greater buildup of oil that results in nodule formation.³

Evidence suggests that Black or Afro-Caribbean people are more likely to get nodular acne, or acne in general, and Thai people are the least likely. This is based on the frequency of repeats within genetic sequences that code for androgen receptors (more repeats mean more androgen receptor expression) thus, a higher chance of developing nodular acne.⁴  As stated throughout this article, ethnicity is a risk factor and does not definitively determine an individual’s likelihood of having nodular acne. However, the frequency of AR repeats is causative and inherited.

Hormonal changes

As described above, nodular acne can be inherited, whereby the responsible genes cause excess hormonal secretion. Testosterone is a type of androgen present in both those assigned male and assigned female at birth (AMABs and AFABs), which is able to be converted into oestrogen.⁵ 

Polycystic ovary syndrome (PCOS) is a medical condition characterised by hormonal imbalance. It affects AFABs, i.e., individuals who possess ovaries.⁶ Ovaries become enlarged whereby several follicles (fluid-filled sacs) develop. Eggs are not released, which interferes with menstruation regularity and subsequently, infertility. Due to hormone imbalance, the likelihood of nodular acne is higher than those without PCOS.⁷ 

Menopause may cause the extent of the symptoms associated with PCOS to change, depending on the person. It is important to remember, however, that there is no known cure for PCOS, so any nodular acne that you may experience cannot be ruled out in your later years.^8,9 

Biological sex

AFABs have a higher likelihood of encountering nodular acne than AMABs, especially during years when hormones are most active, during puberty. AFABs produce more oestrogen and progesterone than AMABs, two hormones that greatly influence the onset of acne.^6,10 

If you partake in hormone replacement therapy (HRT), for example as part of gender reassignment, you may notice acne formation or intensifying if you have increased levels of testosterone or progesterone.¹⁰ As hormones are given gradually during HRT, the emergence of acne is not generally sudden. If you are transitioning to be female, nodular acne is more likely to emerge near the start of HRT, whereas it is less likely to occur if transitioning to male and likely to disappear if you had it prior to the start of treatment.¹¹ 

Skincare habits

Some cosmetic products have comedogenic properties, meaning they tend to clog pores on the skin, usually as an adverse effect. Some examples of compounds known to worsen or bring about the effects of acne include:

• Lanolin, used for irritated and dry skin. It is grease secreted from sheep’s sebaceous glands. Using products containing lanolin greatly increases your chances of causing acne, regular or nodular. Sudocrem is a well-known lanolin-based product.⁴
• Carrageenan is a chemical found in plankton and algae known to be comedogenic. Algae extract products make drier skin oilier, but use in excess could bring about acne.¹²
• Parabens are a group of preservatives. Initially considered effective at preventing bacterial or fungal growth on the skin, they are now believed to stimulate oestrogen production. As a result, parabens-containing products have a tarnished reputation, but these are still important to be aware of, especially if you have PCOS.^{13 ]}
• Coconut oil can make the skin oilier, which is to be expected due to its hydrating and moisturising properties. Coconut oil is comedogenic, blocking pores alongside accumulated dead cells and bacteria that infect the skin.¹⁴

Medications

Corticosteroids are a type of medication that have a broad spectrum of uses – they are given to patients who experience asthma, allergic reactions, rheumatoid arthritis and even inflammatory bowel syndrome (IBS). One of the adverse effects of corticosteroids is their tendency to leave sebaceous glands (responsible for oil production) susceptible to infection. Consequently, this can cause pores to be blocked with bacteria and dead skin, which can lead to acne formation.¹ Nodular acne is likely since large areas of blockage speed up the rate of oil accumulation, leading to nodule formation.

On the other hand, research has detailed how intralesional corticosteroids (applied within the skin to reduce scar formation) can reduce inflammation in areas of the face where acne breakouts occur. Rather than a measure to prevent nodular acne, this is being considered as treatment to minimise the scarring effects caused by the condition, thus improving quality of life.¹⁵

Diet

While evidence is not specific regarding diet’s link to nodular acne, it can be relevant. The differences in cases of nodular acne and ethnicity may not be based on genetic grounds, but on specific nutritional components that are more common in the Western world. Two of these components, IGF-1 and leucine, have been suggested as relevant.⁴

• Internal levels of IGF-1 are known to increase when we eat foods with a high glycaemic index, which is a representation of how blood glucose concentration increases depending on certain food intake. Sugary foods have a high glycaemic index leading to higher IGF-1 expression and a higher chance of developing nodular acne.²
• Leucine is an amino acid, one of the building blocks of proteins. More specifically, it is an essential amino acid, meaning that the human body does not produce it and it must be obtained from food. While the function of leucine is crucial throughout the human body, it is thought to also be responsible for driving acne.¹⁶ Leucine is abundant in cow milk and meat, gouda cheese and yoghurt, which are typically associated with Western diets.

You can talk to a dietician if you have concerns about how diet could affect your relationship with nodular acne, but you can also cut certain foods out of your diet, and if you do experience regular or nodular acne, observe if there are any changes to your condition.¹⁷ While seeking advice from a medical professional is always recommended, temporary exclusion of certain foods is generally harmless.

Summary

Not only are there several risk factors that influence the likelihood of developing nodular acne, but they all seem to be linked to each other to some degree. Acne is inherently a hormonal issue, which is determined by genetics and lifestyle. While nodular acne may be inevitable for some people, understanding what factors affect it can help you identify how to minimise its impact on your quality of life.