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Chickenpox

Disease Details

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Description: Chickenpox is a highly contagious viral infection characterized by an itchy rash and red spots or blisters all over the body.
Type: Chickenpox is a viral infection caused by the varicella-zoster virus. It is not genetically transmitted; rather, it is highly contagious and spread through respiratory droplets or direct contact with the fluid from chickenpox blisters.
Signs And Symptoms: The early (prodromal) symptoms in adolescents and adults are nausea, loss of appetite, aching muscles, and headache. This is followed by the characteristic rash or oral sores, malaise, and a low-grade fever that signal the presence of the disease. Oral manifestations of the disease (enanthem) not uncommonly may precede the external rash (exanthem). In children the illness is not usually preceded by prodromal symptoms, and the first sign is the rash or the spots in the oral cavity. The rash begins as small red dots on the face, scalp, torso, upper arms and legs; progressing over 10–12 hours to small bumps, blisters and pustules; followed by umbilication and the formation of scabs.At the blister stage, intense itching is usually present. Blisters may also occur on the palms, soles, and genital area. Commonly, visible evidence of the disease develops in the oral cavity and tonsil areas in the form of small ulcers which can be painful or itchy or both; this enanthem (internal rash) can precede the exanthem (external rash) by 1 to 3 days or can be concurrent. These symptoms of chickenpox appear 10 to 21 days after exposure to a contagious person. Adults may have a more widespread rash and longer fever, and they are more likely to experience complications, such as varicella pneumonia.Because watery nasal discharge containing live virus usually precedes both exanthem (external rash) and enanthem (oral ulcers) by 1 to 2 days, the infected person actually becomes contagious one to two days before recognition of the disease. Contagiousness persists until all vesicular lesions have become dry crusts (scabs), which usually entails four or five days, by which time nasal shedding of live virus ceases. The condition usually resolves by itself within a week or two. The rash may, however, last for up to one month.Chickenpox is rarely fatal, although it is generally more severe in adult men than in women or children. Non-immune pregnant women and those with a suppressed immune system are at highest risk of serious complications. Arterial ischemic stroke (AIS) associated with chickenpox in the previous year accounts for nearly one third of childhood AIS. The most common late complication of chickenpox is shingles (herpes zoster), caused by reactivation of the varicella zoster virus decades after the initial, often childhood, chickenpox infection.
Prognosis: The duration of the visible blistering caused by varicella zoster virus varies in children usually from four to seven days, and the appearance of new blisters begins to subside after the fifth day. Chickenpox infection is milder in young children, and symptomatic treatment, with sodium bicarbonate baths or antihistamine medication may ease itching.
In adults, the disease is more severe, though the incidence is much less common. Infection in adults is associated with greater morbidity and mortality due to pneumonia (either direct viral pneumonia or secondary bacterial pneumonia), bronchitis (either viral bronchitis or secondary bacterial bronchitis), hepatitis, and encephalitis. In particular, up to 10% of pregnant women with chickenpox develop pneumonia, the severity of which increases with onset later in gestation. In England and Wales, 75% of deaths due to chickenpox are in adults. Inflammation of the brain, encephalitis, can occur in immunocompromised individuals, although the risk is higher with herpes zoster. Necrotizing fasciitis is also a rare complication.Varicella can be lethal to individuals with impaired immunity. The number of people in this high-risk group has increased, due to the HIV epidemic and the increased use of immunosuppressive therapies. Varicella is a particular problem in hospitals when there are patients with immune systems weakened by drugs (e.g., high-dose steroids) or HIV.Secondary bacterial infection of skin lesions, manifesting as impetigo, cellulitis, and erysipelas, is the most common complication in healthy children. Disseminated primary varicella infection usually seen in the immunocompromised may have high morbidity. Ninety percent of cases of varicella pneumonia occur in the adult population. Rarer complications of disseminated chickenpox include myocarditis, hepatitis, and glomerulonephritis.Hemorrhagic complications are more common in the immunocompromised or immunosuppressed populations, although healthy children and adults have been affected. Five major clinical syndromes have been described: febrile purpura, malignant chickenpox with purpura, postinfectious purpura, purpura fulminans, and anaphylactoid purpura. These syndromes have variable courses, with febrile purpura being the most benign of the syndromes and having an uncomplicated outcome. In contrast, malignant chickenpox with purpura is a grave clinical condition that has a mortality rate of greater than 70%. The cause of these hemorrhagic chickenpox syndromes is not known.
Onset: The onset of chickenpox typically begins with a prodromal phase that includes mild fever, malaise, headache, and loss of appetite. These symptoms usually occur 1-2 days before a characteristic itchy rash appears. Initially, the rash presents as red spots that quickly evolve into fluid-filled blisters.
Prevalence: Chickenpox, caused by the varicella-zoster virus, is highly contagious and primarily affects children. The prevalence of chickenpox varies globally. In countries with widespread vaccination programs, the incidence has significantly decreased. For instance, in the United States, the introduction of the varicella vaccine in 1995 led to a substantial decline in cases. However, in regions without routine vaccination, chickenpox remains common. Exact prevalence rates can vary year by year and between different geographical areas, but in non-immune populations, nearly all individuals could potentially contract the disease by adulthood.
Epidemiology: Primary varicella occurs in all countries worldwide. In 2015 chickenpox resulted in 6,400 deaths globally – down from 8,900 in 1990. There were 7,000 deaths in 2013. Varicella is highly transmissible, with an infection rate of 90% in close contacts.In temperate countries, chickenpox is primarily a disease of children, with most cases occurring during the winter and spring, most likely due to school contact. In such countries it is one of the classic diseases of childhood, with most cases occurring in children up to age 15; most people become infected before adulthood, and 10% of young adults remain susceptible.
In the United States, a temperate country, the Centers for Disease Control and Prevention (CDC) do not require state health departments to report infections of chickenpox, and only 31 states volunteered this information as of 2013. A 2013 study conducted by the social media disease surveillance tool called Sickweather used anecdotal reports of chickenpox infections on social media systems Facebook and Twitter to measure and rank states with the most infections per capita, with Maryland, Tennessee and Illinois in the top three.In the tropics, chickenpox often occurs in older people and may cause more serious disease. In adults, the pock marks are darker and the scars more prominent than in children.
Intractability: Chickenpox is not considered intractable. It is generally a self-limiting disease, which means it usually resolves on its own without causing serious long-term effects. Most cases of chickenpox are mild, particularly in children, and can be managed with symptomatic treatment such as antihistamines for itching and acetaminophen for fever. However, complications can arise in certain populations, such as adults, pregnant women, and immunocompromised individuals. In these cases, antiviral medications may be used to reduce the severity and duration of the illness.
Disease Severity: Chickenpox, caused by the varicella-zoster virus, typically results in a mild illness for children, with symptoms like an itchy rash, fever, and fatigue. However, it can be more severe in adolescents, adults, pregnant women, newborns, and individuals with weakened immune systems, potentially leading to complications such as pneumonia, encephalitis, or bacterial infections.
Healthcare Professionals: Disease Ontology ID - DOID:8659
Pathophysiology: Exposure to VZV in a healthy child initiates the production of host immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) antibodies; IgG antibodies persist for life and confer immunity. Cell-mediated immune responses are also important in limiting the scope and the duration of primary varicella infection. After primary infection, VZV is hypothesized to spread from mucosal and epidermal lesions to local sensory nerves. VZV then remains latent in the dorsal ganglion cells of the sensory nerves. Reactivation of VZV results in the clinically distinct syndrome of herpes zoster (i.e., shingles), postherpetic neuralgia, and sometimes Ramsay Hunt syndrome type II. Varicella zoster can affect the arteries in the neck and head, producing stroke, either during childhood, or after a latency period of many years.
Carrier Status: Chickenpox is caused by the varicella-zoster virus. Individuals with chickenpox are not considered carriers in the traditional sense; they actively display symptoms and can spread the virus to others. After recovery, the virus can remain dormant in the body and may reactivate later in life as shingles (herpes zoster). During the acute phase of chickenpox, individuals are highly contagious, typically from 1-2 days before the rash appears until all the blisters have formed scabs.
Mechanism: Chickenpox, caused by the varicella-zoster virus (VZV), is an infectious disease that primarily affects the skin and mucous membranes.

**Mechanism:**
1. **Transmission:** The virus spreads through respiratory droplets or direct contact with the fluid from varicella lesions.
2. **Initial Infection:** VZV enters the body via the respiratory tract, then infects the regional lymph nodes, leading to primary viremia.
3. **Secondary Viremia:** After replication in the liver and spleen, the virus re-enters the bloodstream, causing secondary viremia. This leads to the characteristic vesicular rash.

**Molecular Mechanisms:**
1. **Entry and Fusion:** The VZV glycoproteins (gB, gH, and gL) facilitate viral attachment and fusion with host cell membranes.
2. **Replication and Transcription:** Inside the host cell, the virus uncoats, releasing its double-stranded DNA into the nucleus, where it uses host cellular machinery for replication and transcription.
3. **Viral Assembly:** Newly formed viral particles are assembled in the host cell nucleus and transported to the cell membrane for release.
4. **Immune Evasion:** VZV evades the immune system through several strategies, including downregulation of major histocompatibility complex (MHC) class I molecules and interference with interferon signaling pathways.

These steps collectively lead to the symptoms and spread of chickenpox within the host.
Treatment: Treatment mainly consists of easing the symptoms. As a protective measure, people are usually required to stay at home while they are infectious to avoid spreading the disease to others. Cutting the fingernails short or wearing gloves may prevent scratching and minimize the risk of secondary infections.Although there have been no formal clinical studies evaluating the effectiveness of topical application of calamine lotion (a topical barrier preparation containing zinc oxide, and one of the most commonly used interventions), it has an excellent safety profile. Maintaining good hygiene and daily cleaning of skin with warm water can help to avoid secondary bacterial infection; scratching may increase the risk of secondary infection.Paracetamol (acetaminophen) but not aspirin may be used to reduce fever. Aspirin use by someone with chickenpox may cause serious, sometimes fatal disease of the liver and brain, Reye syndrome. People at risk of developing severe complications who have had significant exposure to the virus may be given intra-muscular varicella zoster immune globulin (VZIG), a preparation containing high titres of antibodies to varicella zoster virus, to ward off the disease.Antivirals are sometimes used.
Compassionate Use Treatment: For chickenpox (varicella), treatment generally focuses on relieving symptoms, as the disease is typically self-limiting in healthy individuals. However, certain situations may call for compassionate use or off-label/experimental treatments:

1. **Compassionate Use Treatments**:
- In severe or high-risk cases (e.g., immunocompromised individuals), compassionate use of antiviral medications like **acyclovir** or **valacyclovir** may be considered. These antivirals are intended to reduce the severity and duration of the illness.
- **Intravenous immunoglobulin (IVIG)** can be used in high-risk patients, such as those who are immunocompromised or pregnant, to provide passive immunity.

2. **Off-Label or Experimental Treatments**:
- **Famciclovir**, another antiviral, is sometimes used off-label for chickenpox, although it is more commonly prescribed for herpes zoster.
- **Brivudine** is another antiviral that has shown promise in some studies, though it is not widely approved for chickenpox treatment.
- **Monoclonal antibodies** are being explored in clinical trials for potential use in severe cases of varicella, especially in immunocompromised patients.

These treatments are generally reserved for cases where the standard approach is insufficient or where complications are likely to arise. Consulting with a healthcare provider is essential for determining the appropriate course of action.
Lifestyle Recommendations: For chickenpox, the following lifestyle recommendations are advised:

1. **Isolation**: Stay away from others, particularly those who haven't had chickenpox or the vaccine, to prevent the spread of the virus.
2. **Rest**: Ensure plenty of rest to help the body fight off the infection.
3. **Hydration**: Drink ample fluids to stay hydrated.
4. **Itch Management**: Use calamine lotion and take cool baths with baking soda, uncooked oatmeal, or colloidal oatmeal to soothe itching.
5. **Avoid Scratching**: Keep fingernails trimmed to prevent skin infections caused by scratching.
6. **Comfortable Clothing**: Wear loose, soft clothing to avoid irritating the skin.
7. **Medication**: Use acetaminophen to reduce fever and pain, but avoid aspirin due to the risk of Reye's syndrome. Antihistamines may help alleviate itching.
8. **Monitor Symptoms**: Keep an eye on any worsening symptoms and consult a healthcare provider if complications arise.

These measures can help manage symptoms and reduce transmission of the virus.
Medication: For chickenpox, the primary treatment focuses on relieving symptoms. Over-the-counter medications such as acetaminophen or ibuprofen can be used to reduce fever and alleviate pain. Calamine lotion and antihistamines may help relieve itching. In some cases, antiviral medications like acyclovir may be prescribed, particularly for those at higher risk of complications. It's important to stay hydrated and avoid scratching to prevent secondary infections. Always consult with a healthcare professional before starting any medication.
Repurposable Drugs: For chickenpox (varicella), there are no widely recognized and approved repurposable drugs specifically indicated for treatment beyond the standard antiviral therapies. A commonly used antiviral medication for chickenpox is acyclovir, which reduces the severity and duration of the illness if administered early. No data is available (nan) for novel or experimental repurposable drugs in the context of treating chickenpox effectively. Further research could potentially identify new therapeutic candidates.
Metabolites: Chickenpox, caused by the varicella-zoster virus (VZV), doesn't have specific metabolites unique to the disease itself. However, infection and the immune response can alter various metabolites in the body, such as cytokines, antibodies, and acute-phase reactants, reflecting inflammation and immune activation. Furthermore, general symptoms like fever and skin lesions result from the body's response to the virus rather than from specific viral metabolites.
Nutraceuticals: There are no specific nutraceuticals universally recommended for the treatment of chickenpox. Chickenpox is a viral infection caused by the varicella-zoster virus, and the primary treatment focuses on managing symptoms. This typically includes:

- Antihistamines for itching
- Paracetamol (acetaminophen) for fever
- Calamine lotion for skin discomfort

It's essential to consult healthcare providers for personalized recommendations and treatment plans.
Peptides: Chickenpox is caused by the varicella-zoster virus (VZV). If you meant to ask about "peptides" in relation to chickenpox, these are short chains of amino acids that can be part of the immune response to the virus, potentially useful in vaccine development or diagnostic tests. "Nan" might refer to "nanotechnology," which can be leveraged for creating more effective vaccines or antiviral treatments by using nanoparticles to deliver medications or genetic material directly to infected cells.