July 10, 2025 Author : Saraiva da Cunha (infectious diseases) Shingles, or herpes zoster, is a viral infection that affects the nervous system and is mainly characterized by a painful rash on the skin forming a band or stripe . Shingles is caused by the varicella-zoster virus, which is a herpesvirus. This virus remains latent, or dormant, in the body's nerve cells after having chickenpox, without causing any symptoms. However, it later reactivates in about 20%-30% of people and causes shingles. Only people who have had chickenpox can develop shingles. It is possible to have shingles more than once. It is not known exactly why the varicella-zoster virus reactivates. What is known is that shingles is most common: In adults, most often after the age of 50, which is associated with the greater weakness of the immune system with ageing. In people who for other reasons have a weakened immune system, for example, due to chronic diseases, chemotherapy treatments and immunosuppressive treatments. However, shingles can occur at any age, as long as the person has had chickenpox, and also in healthy people. The Portuguese Association of General and Family Medicine (APMGF) estimates that in Portugal, between July 2023 and June 2024, 62,985 adults were diagnosed with herpes zoster infection, of which 67% were over 50 years old (Observador, November 25, 2024). Shingles is not contagious , that is, it I not possible to “catch” shingles through contact with another person. However, those who have never had chickenpox can become infected by the virus through direct contact with shingles lesions or through the respiratory tract, and then develop chickenpox. Shingles symptoms The initial symptom of shingles is a strange feeling of discomfort that includes pain, burning and tingling in the area where the rash will appear a few days later. Low-grade fever and headache are also common. A few days later (1-2 days), a unilateral rash (affecting only on one side of the body) appears . The skin becomes red, with small blisters or vesicles, filled with fluid, which appear grouped forming bands of varying dimension, but always located or progressing along a dermatome. A dermatome is a region of the skin that is innervated by a spinal nerve. The most frequently affected areas are the dermatomes including the chest and back at the same level and the belly and lower back, but any dermatome can be affected. The blisters rupture 4-5 days after they appear, forming small ulcers . This is when there is a greater risk of infection. The b listers begin to dry out and form crusts 7-10 days after the rash appears. It can take four to five weeks between the first symptoms and the complete disappearance of the rash. Diagnosis and treatment The diagnosis of shingles is based mainly on the symptoms presented and the history reported. It can be confirmed by testing the fluid from the blisters for the virus . When diagnosed in the first 3 days, treatment of shingles is more effective, with antiviral medications that reduce the duration and intensity of the symptoms. It usually also includes analgesics to relieve pain and any necessary support measures. It is important that the areas of the rash are kept very clean and dry and that no products are applied without medical advice . Complications of shingles The most common complication of shingles is a persistent pain – called post-herpetic neuralgia – which can be severe and last for years. It occurs in about 10%-15% of people who have shingles, especially in older people. In about 2% of cases, the rash can become infected, which delays its resolution. When the rash affects areas of the head, eye infections can occur (2% of cases) with possible loss of vision if not treated timely and, more rarely, involvement of the auricular nerves and the facial nerve. Prevention of shingles Shingles can be prevented in people who have had chickenpox through vaccination , which significantly reduces the likelihood of developing the disease and its severity. Children who have been vaccinated against chickenpox are less likely to have shingles compared to those who have been infected with the wild virus. People with shingles should stay away from other people , particularly pregnant women, until the rash disappears completely to avoid transmitting the virus to those who have not had chickenpox. Sources Albrecht MA. Shingles. uptodate.com CDC. Shingles (Herpes zoster) . Patil A, Goldust M, Wollina U. H erpes zoster: a review of clinical manifestations and management . Viruses 2022;14:192. Meet the infectious diseases clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
