Everyone has that one chief skin concern they wish would just bugger off. For some, it's pigmentation. For others, it's acne. For others still, it's eczema. 

We know you're familiar with them, because these guys are popular kids on the skincare block. We tend to talk about them a LOT because they're super common, annoying and everyone wants to know how to get rid of them. (So, yeah wish they'd all stop bragging.)

Watch: Who wants some nifty little skin tips? Of course you do! Check out how to improve your skin while sleeping. Post continues below. 

But there are some other common skin conditions out there that don't get nearly enough airtime.

We're talking about the skin things that seem to fall into this ~mysterious~ kinda category - which is just super unhelpful for anyone that suffers with them.

Darkened underarms is one of those things.

While it might not sound like anything major, darkened underarms is actually a really common skin condition that has a proper name and everything. It's called acanthosis nigricans (AN).

Just for the record - no one has perfect skin. Listen to this episode of You Beauty, where Angie Kent gets real about skin issues. Post continues. 

Studies show that it affects more than 10,000 people per year in Australia and the prevalence varies according to age, race and body weight. So if you've got it - you're not alone!

While it's a fairly harmless condition for the most-part, AN can offer a real swift kick to people's self-confidence. Especially come summer.

So, we've asked dermatologist Dr Cara McDonald from Complete Skin Specialists to tell us a bit about AN, and what options are available for those who want to look at treatment.

So, what causes dark underarms? 

AN is characterised by the darkening of skin, which may be due to pigment cells multiplying way faster than normal. While it's not a painful skin condition, thickened skin on your underarms can be annoying to deal with.

Dr McDonald said, "The exact cause of acanthosis nigricans is not completely understood, but it is considered to be a sign of underlying disorders rather than a skin problem in itself."

That sounds... not good. What does this mean?

Well, for starters, Dr McDonald said people who are overweight are more likely to notice dark skin in their underarms and other areas of their body - such as their groin and neck. And apparently it could flag a major health concern.

"It is most frequently seen in overweight patients and is thought to be related to insulin resistance," she said.

If you're not familiar with what insulin resistance means, it's basically a condition where your body struggles to make insulin (a hormone) which reduces the sugar in your blood (you use this for energy). This increases the risk of developing diabetes.

Are there any factors that increase the likelihood of dark underarms?

Other things that might increase the likelihood of AN include certain medications and people who have hormonal disorders, like polycystic ovary syndrome. 

"Hormonal and metabolic disorders, such as diabetes mellitus, metabolic syndrome (obesity and cardiac risk factors), polycystic ovarian syndrome and thyroid disease, can all be associated with acanthosis nigricans," explained Dr McDonald.

It also may simply be the result of genetics and race. "It’s more frequent and more severe in patients with darker skin colouring."

Who can get it?

Anyone of any age can develop AN - male or female. And (as mentioned) it's also common for the condition to appear on other areas of the body. 

So don't freak out if you're experiencing it somewhere else, as well as on your underarms.

Are there any risk factors associated with acanthosis nigricans?

So, is AN actually a cause for concern?

According to Dr McDonald, it's usually nothing to worry about. However, if you are experiencing severe AN, it could be worth checking in with your doctor to make sure everything is okay. 

"In rare cases, acanthosis nigricans can be related to underlying cancers, mainly of the gastrointestinal tract," said Dr McDonald. "These cases tend to be more severe and have a relatively sudden onset."

What treatment options are available?

Alright - let's be straight. Acanthosis nigricans is not an easy skin condition to treat, but Dr McDonald said it "often improves with correction of causative factors". 

Meaning, while there's no exact 'cure' for it, diet and lifestyle changes may help manage the appearance of AN. 

Weight management, as well as normalising insulin levels, can often result in improvement in the skin, Dr McDonald said.

If you're wondering what kind of topical treatments can help, prescription skincare is probably your best bet. Prescription creams, ointments, and gels are available to help reduce skin discolouration and improve the appearance of the underarms. 

However, it's worth noting you may not see a dramatic improvement - especially if you're suffering from severe AN. If this is the case, a dermatologist may prescribe oral medication to help treat it - but again, effectiveness of this treatment is all dependent on the individual.

Dr McDonald said in-clinic laser treatments may also help to lighten underarm skin, but it's best to check in with your doctor or dermatologist first to make sure this is the right treatment for you.

Feature: Getty

Do you have dark underarms? What is your go-to treatment? Share with us in the comment section below.