Cases of highly infectious skin bug scabies are surging across the UK, with cases occurring 'out of nowhere' and whole households affected.

The condition, caused by microscopic mites that burrow into the skin, causes intense itching — and easily spreads if people are in close contact.

If not properly treated the infestation can linger for months or even years, while the parasite and its eggs can also live in bedsheets and towels.

Health officials are now warning the public to be vigilant of the symptoms.

Professor Kamila Hawthorne, Chair of the Royal College of GPs, said: 'If not properly treated, scabies can quickly spread and increase a patient's risk of complications such as secondary skin infections or make existing skin conditions worse.'

Diagnosing scabies can be challenging as it can take up to eight weeks for the tell-tale red raised rash, which affects the skin folds inside the elbow, knee, buttocks and between fingers and toes, to appear. 

In its early stages, an intense itch, which is worse at night, might be the only symptom. 

Later, red raised 'trails' or dots, where the mites tunnel to lay eggs, will be visible.

Some 3,689 cases were diagnosed in hospitals in England in the year to April – up from 2,128 the previous year, according to NHS figures reported by the BBC.

Dur to the way the bug transmits, outbreaks are most common among schoolchildren, young adults — who may pick it up through sexual transmission — and in care homes.  

Those with weaker immune systems may be vulnerable to a more severe form of the disease, crusted scabies, which involves a higher density of mites.

The scratching can also exacerbate other skin conditions like eczema or psoriasis and can lead to complications such as bacterial infections.

It is a myth, however, that scabies is linked to poor hygiene — regular washing makes no difference and anyone can be affected.

Professor Kamila Hawthorne, Chair of the Royal College of GPs, said: 'While not a serious condition, scabies can be very itchy and irritating, and can be easily contracted through close physical contact.'

She confirmed that doctors were seeing rising cases with the majority of cases in the north of England, and urged people to seek medical help if they suspect they are infected. 

'Patients may be apprehensive to seek treatment given the social stigma that surrounds the condition, but it is important that they don't ignore their symptoms. 

'Doing so risks transmitting the condition to other people – particularly if they are living in close proximity to others such as on a university campus.' 

The BBC has heard from people at five universities around the country, who spoke of multiple cases arising 'out of nowhere'. 

One student said he noticed 'tiny red dots' along his wrist that began spreading.

'One of my housemates came out to the house that she had scabies at the time as well. So then I was like, "Okay, so do I",' he added. 

Another student reported that they had been trying, unsuccessfully, to rid themselves of the infection for 'two to three months'. 

Treating scabies involves rubbing an anti-parasite lotion — permethrin or malathion — into the skin all over the body, including under the nails, and keeping it on for at least between eight and 12 hours. 

This means reapplying it every time a person washes their hands. The process must be repeated seven days later to ensure all mites and their eggs have been destroyed.

Everyone in the same household, and any sexual partners over the last eight weeks, must also apply it, even if they don’t have symptoms.

As previous reported by MailOnline, previous outbreaks have led to shortages of permethrin. 

Doctors can also now prescribe ivermectin, which comes as a pill, as an alternative.

With winter approaching, which is typically when scabies cases reach their peak, the British Association of Dermatologists (BAD) is warning the public, particularly those in group living facilities, to be on alert for signs of these pests. 

Dr Tess McPherson, of the BAD, said: 'We would urge people who suspect they may have scabies, or who still have scabies, to seek medical treatment for this incredibly contagious skin condition at the earliest opportunity.'