Overview 

Shingles, also known as herpes zoster, is a viral infection of the nerves and the skin around them that causes a painful rash. It is caused by the varicella-zoster virus (VZV), which is the same virus that causes chickenpox. Shingles typically appear as a single stripe of blisters that wrap around a localised area of the body (e.g., either the left or right side of the torso) and rarely cross over. However, shingles can occur almost anywhere on the body, including the face, eyes, and genitals. This article will discuss the causes and symptoms of shingles.¹ 

Symptoms 

The symptoms of shingles can be divided into three stages: prodromal (pre-eruptive) stage, eruptive stage, and chronic stage.²

Prodromal (pre-eruptive) stage

The prodromal stage of shingles, also known as the pre-eruptive phase, is the initial stage before the characteristic blister-like rash appears. It usually lasts 1 to 5 days before the rash appears.

Symptoms of the prodromal phase can include:

• Pain, burning, or tingling sensations in the area where the rash will develop. The pain may be constant or intermittent
• Itching or sensitivity to touch of the affected area
• Generally feeling unwell, fever, headache, and fatigue 

The pain can be sharp or dull and can often be mistaken for other conditions, such as migraines, dental problems, heart issues, or musculoskeletal pain, depending on the location of the prodromal symptoms.

Eruptive stage 

The eruptive stage of shingles is the phase when the characteristics of rash and blisters appear. This stage usually lasts 2 to 4 weeks. Symptoms of the eruptive stage can include:

• A rash that quickly becomes fluid-filled blisters that appears in a single stripe or band on one side of the body
• Blisters eventually burst and form crusts or scabs
• Pain associated with the rash can be severe and is usually localised to the area of the blisters. The pain is often described as burning, throbbing, or stabbing 
• Fever 
• Chills
• Headache
• Upset stomach
• Swelling and tenderness of the lymph nodes near the affected area may occur

Chronic stage (post-herpetic neuralgia)

The chronic stage of shingles, also known as post-herpetic neuralgia, can develop after the acute rash and blisters have healed. This stage is characterised by persistent nerve pain and other symptoms in the area where the shingles outbreak has occurred. It can last months or even years after the rash has healed. 

Symptoms of the chronic phase can include:

• Persistent pain in the area where the shingles rash occurred, even after the skin lesions have healed
• The pain can be intense and tiring
• Itching and numbness may also be present

Post-herpetic neuralgia is more common in older adults and can significantly affect quality of life. 

Causes

Shingles result from the reactivation of the varicella-zoster virus. The initial encounter with the virus typically occurs during childhood, resulting in chickenpox (varicella). Once an individual recovers from chickenpox, the virus remains in their body. The virus moves from the skin lesions along sensory nerve fibres to the nerve cell bodies found in the dorsal root ganglia, which are groups of nerve cells located close to the spinal cord. At this point, the virus enters a dormant state, staying inactive for many years or even decades. However, it is important to note that not everyone who has had chickenpox will develop shingles.³

Is shingles contagious? 

Shingles itself is not contagious, but the virus that causes it, the varicella-zoster virus, can. It can spread from one person with active shingles to another who has never been infected with the virus i.e. got chickenpox or the vaccine. This transmission can cause the uninfected person to develop chickenpox, not shingles. The virus can spread through direct contact with the fluid from shingles blisters. Although less common, the virus can spread through indirect contact with items contaminated with the fluid from the blisters (e.g., clothing, toys, or bedding). Once the blisters have crusted over, they are no longer contagious.^1,2

Risk factors

The reason why shingles may appear later in life is unclear. Certain risk factors may increase a person’s risk of developing shingles. These risk factors can include:^1,4,5,6

• Age: the risk of shingles increases with age, especially in people over 50. The immune system tends to weaken as people get older, making them more susceptible to the reactivation of the varicella-zoster virus
• Weakened immune system: certain illnesses can compromise the immune system, such as HIV/AIDS and cancer, and chronic illnesses such as autoimmune diseases, diabetes, and chronic kidney disease can increase the risk of shingles. Also, certain medications, such as immunosuppressive drugs or chemotherapy, can weaken the immune system
• Previous history of chickenpox: those who have had chickenpox are at risk because the varicella-zoster virus remains dormant in the body and can reactivate later in life as shingles 
• Stress and emotional factors: high levels of stress and emotional trauma can weaken the immune system and can reactivate the virus
• Physical trauma: injury or surgery that affects the nerves where the virus is dormant can sometimes trigger shingles

Complications of shingles

Most people can recover from shingles without experiencing any long-term consequences. However, in some cases, shingles can cause complications, such as: ⁷

• Post-herpetic neuralgia: is long-term nerve pain that continues for months or even years after the shingles rash has healed
• Vision loss: when shingles affect the eyes, it is known as herpes zoster ophthalmicus, which can cause complications such as vision loss, glaucoma, or scarring if not treated quickly
• Hearing problems: when shingles affect the ears, it can lead to Ramsay Hunt syndrome
• Skin infections: the blisters caused by shingles can become infected with bacteria and can cause severe skin infections such as cellulitis
• Neurological problems: shingles can affect the nervous system in several ways including encephalitis, meningitis, and peripheral nerve damage

FAQs

Do you have to isolate with shingles?

No, there are formal quarantine requirements, however, it is preferred not to go to work or school if you have developed the shingles.

Can you shower when you have shingles?

Preferably not, because hot water can increase blood flow worsening the shingles.

What is the best painkiller for shingles?

Over-the-counter pain medication like paracetamol or ibuprofen can work but in some cases, prescription or stronger pain relievers might be given depending on the severity of the pain.

When day does the pain of shingles peak?

Usually 4-5 days after symptoms show.

Summary 

Shingles, also known as herpes zoster, is a significant viral infection caused by the varicella-zoster virus, the same virus that is responsible for chickenpox. After a person recovers from chickenpox, the virus remains dormant in the nerve tissues and can reactivate years later as shingles. This condition is characterised by a painful rash that typically appears as a stripe of blisters on one side of the body but can appear anywhere including the face, eyes and genitals. Shingles progresses through three stages: the prodromal (pre-eruptive) phase, marked by initial sensations such as pain, burning, or tingling, the eruptive stage, characterised by the development of a rash and fluid-filled blisters, accompanied by severe localised pain, and the chronic stage, known as postherpetic neuralgia, where persistent nerve pain can linger long after the rash has healed.

Several risk factors increase the likelihood of developing shingles, including advancing age, a weakened immune system due to medical conditions or treatments, a history of chickenpox, high-stress levels, and physical trauma. Shingles can lead to several complications, including postherpetic neuralgia, vision and hearing problems, skin infections, and neurological issues. Early diagnosis and treatment can help mitigate these risks and improve outcomes for those affected.