What you need to know about shingles

Shingles is a painful rash caused by infection with the varicella zoster virus, which also causes chickenpox. 

Chickenpox is a very common infection in the UK and after it resolves, the virus remains in your body.

However, the virus becomes inactive (dormant) and retreats into ganglia, that is, clusters of nerve cells located close to your spine. During this time, the virus doesn’t cause any symptoms; however, if reactivated, it travels along a nerve into your skin, where it causes shingles. 

What triggers shingles?

There are several different reasons why the varicella zoster virus may become reactivated in your body. They all relate to suppression of your immune system. 

Shingles can, therefore, occur if you’re having immunosuppressive treatment, such as chemotherapy or steroid tablets, or if you develop an illness that affects your immune system, such as blood cancers, HIV or any other serious health issue that strains your immune system. 

Stress can also contribute to the reactivation of the virus as this dampens your immune system. Another major factor is age. In older people, the immune system works more slowly, which is why shingles becomes more common the older you get, with most cases reported in the over 60s. 

Signs and symptoms of shingles 

As shingles is caused by the virus travelling down a specific nerve to the skin, it affects only the area of skin supplied by that nerve — this is called a dermatome. A dermatome starts at the midline of your body and extends outwards to the periphery on one side of your body.

The dermatomes most commonly affected by shingles are located on the torso and face; however, shingles can affect any area of your skin, such as that over your buttocks and legs. 

Before the rash develops, you may experience a tingling or burning sensation in the affected area of skin, which can be very painful. This usually lasts three to four days before the rash becomes apparent. 

The rash causes your skin to appear reddened (on light skin) or purplish (on darker skin) with groups of small blisters called vesicles that eventually pop, release clear fluid and crust over. The rash remains on the skin for up to 10 days and takes another two to four weeks to heal. 

A shingles rash can be accompanied by a general feeling of being unwell and a fever. If you’re severely immunosuppressed, shingles can affect multiple dermatomes across your body.

After the rash has cleared, your skin may darken (hyperpigmentation) or lighten (hypopigmentation). These effects fade over the next few weeks or months. It is important to protect your affected skin from exposure to the sun by covering the area and using sunblock that is SPF 50 or higher. This will prevent darker skin from darkening further and lighter skin from burning in the sun.

Is shingles contagious?

Shingles is contagious while the rash presents with vesicles. When these vesicles pop, they release fluid containing varicella zoster virus. Direct contact with the skin during this time or with the fluid released from these vesicles (eg from sharing a towel) can transfer the virus onto someone else. 

If the person who is exposed to the virus has not had chickenpox before, they will develop chickenpox but will not develop shingles. If they know they have been exposed, they can see their GP within five days of exposure to receive a chickenpox vaccine. This may prevent chickenpox from developing. 

It is important to note that if you have shingles you will remain contagious until your last vesicle has popped and crusted over. During this time, you should avoid contact with anyone who hasn’t had chickenpox or who is immunosuppressed, as well as the elderly and babies.

What to do if you have shingles

If you are in otherwise good health, are not older than 65 or are not older than 50 and immunosuppressed, and only one dermatome is affected by shingles, you don’t need to see a doctor. You can manage your shingles at home by avoiding contact with vulnerable people while you’re contagious, taking over-the-counter painkillers, applying a soothing emollient daily and resting. If your skin feels itchy, you can apply calamine lotion. Your rash will heal naturally over several weeks.

If multiple dermatomes are affected (ie your rash is widespread), your rash is near your eyes, or you are over 65 or over 50 and immunosuppressed, see your GP for treatment. It is important to see your GP within the first few days of vesicles appearing as treatment aims at reducing the amount of virus present (viral load) from the outset. 

Your GP will ask you about your symptoms and medical history and will prescribe a high dose of an antiviral medication called acyclovir. You will need to take your medication five times a day for a week. 

Diagnosing shingles

In most cases, your GP can diagnose shingles by examining your rash and asking about your symptoms and medical history. 

If your rash is widespread, it can be more difficult to reach a definitive diagnosis based on examination alone, in which case, your GP will pop a vesicle, swab the fluid and send it to the laboratory for testing. 

Complications of shingles

Shingles can lead to a skin infection, especially after your vesicles pop, which may need treatment with a course of antibiotics. 

Shingles can also damage your nerves, leading to a variety of symptoms depending on whether your peripheral nervous system or central nervous system (ie brain and spinal cord) is affected. 

If your central nervous system is affected, you may, for example, develop inflammation of the brain (encephalitis), headaches, vision problems or paralysis. 

The most common complication of shingles is postherpetic neuralgia affecting the peripheral nervous system. This causes severe pain in the skin after the rash has settled. The pain can be so severe that even using a duvet at night isn’t tolerable. It can take a year or more to resolve, and you may need medication to help relieve your pain. 

In the first instance, co-codamol and paracetamol are recommended to relieve pain caused by postherpetic neuralgia, but in more severe cases, you may need antidepressants and/or anticonvulsants.

A specific type of facial paralysis called Ramsay Hunt syndrome is a rare complication of shingles. It is caused by damage to your facial nerve, leading to weakness on one side of your face, increased sensitivity to noise (hyperacusis) and balance problems. 

If your rash is near your eyes, it can cause inflammation of specific parts of your eye. This can lead to a painful red eye, sensitivity to light and vision loss. It is important to seek medical help urgently to avoid permanent damage to your eyes. 

How to reduce your risk of shingles

If you haven’t had chickenpox, avoid anyone with shingles who is still contagious. You can also get vaccinated. This will prevent you from catching the varicella zoster virus in the first place, so you will not be at risk of developing shingles in the future. 

If you have already had chickenpox, vaccination can still help prevent shingles. On the NHS, this is only available to those aged over 50 who are immunosuppressed or those who are over 65 up to the age of 80.