When spots are catching

Most of the spots that dermatologists deal with are caused by acne and similar skin problems. These spots are not infectious and rarely mean that anything else is wrong. However, there are several highly infectious disease that can also cause spots, blisters and pustules on the skin. These include:

• Impetigo
• Chickenpox
• Shingles
• Measles
• Rubella

Some of them can have very serious complications, especially for pregnant women, newborn babies and people with reduced immune systems due to illness, cancer treatment or medication.

Impetigo

Impetigo is a relatively common childhood skin infection that may also affect adults. It is caused by a common skin bacterial infection called staphylococcus. In most cases it mimics acne like spots on the face, often around the nose and mouth. Rarely it can become more severe and create blisters on the skin.

Impetigo typically responds to treatment with either topical or oral antibiotics.

Chicken pox

Chicken pox, or varicella, is a very common childhood disease with relatively mild symptoms. It produces spots almost anywhere on the body, usually starting on the limbs and trunk and spreading to the head and neck, face and scalp. These spots start as small itchy red lumps that rapidly develop a blister in around 12 hours. These blistered spots are incredibly itchy.

Chicken pox is caused by a virus and spreads rapidly through airborne particles in coughs and sneezes. As a result, around 90% of children will develop the disease at some point, making adult chicken pox relatively rare.

There is no cure or treatment for chicken pox and the symptoms will usually pass naturally after one to two weeks. However the virus remains dormant in your body and can return as shingles in later life. Vaccination against chicken pox can help to reduce the severity of any outbreak of chicken pox.

Shingles

If you have had chicken pox, the virus will stay with you and can reappear as shingles. Shingles is most common in people over fifty, and those over 70 are now routinely offered a vaccination on the NHS.

Shingles causes a painful rash, which goes on to become a patch of itchy blisters, though this only ever affects one side of the body and does not cross over the midline. The rash lasts for seven to ten days.

Early treatment with antiviral tablets such as aciclovir can limit the severity of an outbreak and can also help to prevent recurrence if taken long term. Blisters may take up to a month to heal completely.

The main complication of shingles is postherpetic neuralgia, which causes severe pain in the nerves for several months. Around 10% of shingles sufferers will go on to develop this condition, although this proportion increases with age leaving as many as a third of shingles sufferers over 80 affected.

You cannot catch shingles, as it is caused by a dormant virus in your own body. However people with shingles can spread chicken pox infections to others.

Measles

Measles is a highly infectious disease that can have serious complications. It starts as small white spots in the mouth and throat and spreads rapidly across the whole body as a rash of small red/brown spots.

Like chicken pox, measles is a viral disease, which is spread by airborne particles that can survive on surfaces for several hours, making it particularly virulent. Measles can strike at any age, but is particularly common in children between one and four years old.

There is no cure or treatment for measles, and cases should be rare in the UK as all parents are offered the MMR vaccination for their child at the age of 14 months. Uptake of the vaccine did, however, fall a few years ago because of claims that the vaccine was linked with autism. Large studies proved there is no link and vaccination levels have recovered since. Not in time, though, to prevent some measles outbreaks.

Measles can be much more serious in older children and adults, leading to complications such as pneumonia and encephalitis. One in five thousand cases of adult measles results in death.

Rubella

Also known as German measles, rubella is another disease that has become much less common since the introduction of the MMR vaccine.

Rubella causes a rash of small, red spots as well as swollen glands and a fever. In most cases the symptoms are mild and will pass in around a week, although you may experience swollen glands for longer than this.

As with the other diseases, there is no cure or treatment for rubella, other than letting the disease take its natural course. Unfortunately, victims are infectious for around a week before they know they have the disease, so it is difficult to contain an outbreak.

Rubella is particularly dangerous for pregnant women in the first twenty weeks of their term. The virus can seriously harm the baby, causing problems with the eyes, ears and heart as well as brain damage. Fortunately, rubella is very rare, with just 65 cases reported in England and Wales in 2012.