A doctor has discussed how Bella Hadid, her brother Anwar, and their mother Yolanda all ended up with the same illness that frequently affects celebrities.

This follows Bella's recent sharing of a series of alarming photos from her hospital bed (Thursday 18 September), which has raised concerns among her fans.

For those unaware of her health issues, the 28-year-old American model is battling a bacterial infection that not only affects her family but also a large number of other A-listers.

Among the many well-known individuals who have publicly discussed their battles with this illness are Shania Twain, Alec Baldwin, Avril Lavigne, and Justin Timberlake.

The disease reportedly impacts approximately 400,000 individuals in the US annually, while in the UK, there are about 3,000 to 4,000 new cases each year. However, the actual numbers are believed to be significantly higher, as per GOV.uk, since many cases are treated without official laboratory confirmation.

A doctor has explored the rarity of three family members contracting Lyme disease (Chance Yeh/WireImage)

The illness in question is Lyme disease - a bacterial infection transmitted to humans through infected ticks.

Early diagnosis makes it easier to treat, with a prominent symptom being a 'circular or oval-shaped rash' around the tick bite.

Since her diagnosis in 2012, Bella has been open about her battle with the disease, describing how the 'excruciating pain' hinders her ability to perform simple tasks.

She previously shared with Vogue: "Most days, it's difficult to take a shower, which I assure you, if you're reading this, I do shower every day. But sometimes, if I have a day off, just managing a shower and making myself breakfast feels like an achievement."

The model isn't the only one in her family affected by Lyme disease - her brother Anwar and mother Yolanda also contracted it around the same time.

While dealing with her own struggles, Yolanda shared in a heartfelt Instagram update this week that her 'pain cannot compare' to seeing her daughter suffer.

Yolanda Hadid posted photos of her daughter Bella in a hospital bed this week (Instagram/@yolanda.hadid)

She wrote: “As you can imagine, seeing my Bella endure her struggles in silence has pierced the deepest core of hopelessness within me. The invisible disability of chronic neurological Lyme disease is challenging to explain or comprehend for anyone.

"I strive to set an example on our Lyme journey but my own pain is nothing compared to watching my child suffer.”

Yolanda went on: "After many years, I ceased sharing my personal story as I needed a change in energy, time to focus on my healing rather than taking in others’ views about my journey."

Recently, a doctor has explored how surprising it is for three family members to contract Lyme disease, and how unusual this occurrence is.

Speaking to PEOPLE, Dr. Raphael Kellman, the founder of the Kellman Center for Integrative and Functional Medicine, explained that it's actually 'not uncommon for several family members to have Lyme disease'.

He informed the publication: "However, it’s not genetic; rather, it's because they inhabit the same environment.

"A significant factor could be imbalances in the billions of gut bacteria known as the microbiome, those bacteria within our gut that outnumber us 10 to one and maintain our health."

The doctor continued: "It's not unusual for the microbiome to be unhealthy, and if one family member's microbiome is unhealthy, it’s probable that another family member's is as well."

He added that if someone is afflicted with chronic Lyme disease, other underlying conditions, often unnoticed, can exacerbate the issue. These could be genetic, such as low thyroid function, for example.