10 Common Smallpox Symptoms You Should Know About

Smallpox is a serious and highly contagious viral disease caused by the variola virus. Although officially eradicated in 1980 through a global vaccination campaign, understanding smallpox symptoms remains important for medical professionals and public health preparedness. This article explores the key symptoms of smallpox, helping you recognize the warning signs of this once-devastating disease.

Smallpox typically progresses through several distinct stages, with symptoms appearing 7-17 days after exposure to the virus. The disease was known for its characteristic rash and high fever, along with other debilitating symptoms that made it one of the most feared infections in human history.

1. High Fever

One of the first and most prominent symptoms of smallpox is a sudden onset of high fever, typically ranging from 101°F to 104°F (38.3°C to 40°C). This fever appears during the initial phase of the illness, known as the prodrome stage, which occurs before the characteristic rash develops.

The fever associated with smallpox is often accompanied by chills and may persist for 2-4 days. Unlike common viral infections where fever gradually increases, smallpox fever tends to spike rapidly and remains consistently high. This intense fever can cause significant discomfort and is often one of the first signs that prompts individuals to seek medical attention.

Key characteristics of smallpox fever include:

• Sudden and abrupt onset
• Persistent high temperature
• Accompanied by severe body aches
• May cause delirium in severe cases

2. Severe Headache

Intense and persistent headaches are among the earliest symptoms of smallpox infection. These headaches are typically described as severe, throbbing pain that affects the entire head and is not easily relieved by rest or common pain management methods.

The headache associated with smallpox is often more severe than typical tension headaches or migraines. It results from the body’s immune response to the variola virus and the accompanying inflammation. Patients frequently report that the headache is debilitating and interferes with their ability to perform daily activities or even rest comfortably.

The severity of the headache may correlate with the overall severity of the infection, and it typically persists throughout the prodromal phase, only beginning to subside once the characteristic rash appears.

3. Severe Back Pain

Excruciating back pain is a hallmark symptom of smallpox, particularly distinguishing it from other rash-causing illnesses. This pain typically affects the lower back region but can radiate throughout the entire back and even into the legs.

The back pain experienced with smallpox is often described as one of the most painful aspects of the disease during its early stages. This symptom is so characteristic that historical medical texts often emphasized it as a key diagnostic feature. The pain is thought to result from the virus affecting the nervous system and causing widespread inflammation.

Characteristics of smallpox-related back pain:

• Severe and constant pain
• Often described as deep, aching pain
• May worsen with movement
• Can be accompanied by muscle stiffness
• Typically appears before the rash develops

4. Severe Abdominal Pain

Many smallpox patients experience intense abdominal pain during the early stages of infection. This pain can range from generalized discomfort to severe cramping that may be confused with other gastrointestinal conditions.

The abdominal pain associated with smallpox is caused by the systemic effects of the viral infection and inflammation throughout the body. Some patients may also experience nausea and vomiting alongside the abdominal pain, which can lead to dehydration and complicate the clinical picture.

This symptom typically appears during the prodromal phase and may persist as the disease progresses. The severity can vary significantly between patients, with some experiencing mild discomfort while others report debilitating pain that prevents eating or drinking.

5. Characteristic Skin Rash

The most recognizable symptom of smallpox is its distinctive skin rash, which appears 2-4 days after the initial fever and other prodromal symptoms. This rash is what gives the disease its name and is the primary diagnostic feature that distinguishes smallpox from other infections.

The smallpox rash follows a specific progression pattern:

Initial appearance: The rash begins as small, red spots (macules) that first appear on the tongue and in the mouth. These spots quickly develop into sores that break open, releasing large amounts of virus into the mouth and throat.

Spread pattern: Within 24 hours, the rash spreads to the face and then to the arms, legs, hands, and feet. A distinctive feature of smallpox is that the rash appears more concentrated on the extremities and face rather than the trunk, which helps differentiate it from chickenpox.

Evolution stages:

• Macules: Flat, red spots on the skin
• Papules: Raised bumps that develop within 1-2 days
• Vesicles: Bumps fill with clear fluid, becoming firm and round
• Pustules: Vesicles fill with pus, creating the characteristic “pox” appearance
• Scabs: Pustules crust over and form scabs, which eventually fall off leaving scars

A critical diagnostic feature is that all lesions in a given area progress at the same rate, unlike chickenpox where lesions appear in successive crops at different stages.

6. Raised, Firm Pustules

As the smallpox rash progresses, the fluid-filled vesicles transform into raised, firm pustules that have a distinctive appearance. These pustules are characterized by a deep-seated feeling, as if there is a small round object beneath the skin.

The pustules of smallpox have several unique characteristics:

• Umbilicated center: Each pustule has a depression or dimple in the center
• Firm texture: Unlike chickenpox blisters, smallpox pustules feel firm and almost bead-like when touched
• Uniform appearance: All pustules in the same body area look similar and are at the same stage of development
• Distribution: More concentrated on the face, arms, and legs than on the trunk

The pustular stage typically lasts 5-8 days, during which time patients remain highly contagious. The pustules are filled with infectious viral particles, making any contact with them a potential transmission risk.

7. Severe Fatigue and Prostration

Overwhelming fatigue and prostration are significant symptoms of smallpox that can persist throughout the illness. Patients often describe feeling completely exhausted, unable to perform even basic self-care activities without assistance.

This extreme fatigue is more than typical tiredness; it is a profound weakness that affects the entire body. The prostration associated with smallpox can be so severe that patients are bedridden throughout most of the illness. This symptom results from the body’s intense immune response to the viral infection, which requires enormous energy expenditure.

The fatigue typically begins during the prodromal phase and may continue for weeks after the acute illness, even during recovery. Many survivors of smallpox reported that regaining their normal energy levels took considerable time, sometimes months after the visible symptoms had resolved.

8. Vomiting

Vomiting is a common early symptom of smallpox, occurring during the initial prodromal phase of the illness. This symptom can appear alongside or shortly after the onset of fever and may be severe enough to prevent proper nutrition and hydration.

The vomiting associated with smallpox is triggered by the body’s systemic response to the variola virus. It is not typically caused by gastrointestinal infection but rather by the overall toxic effect of the virus on the body and the resulting inflammation.

Important considerations about smallpox-related vomiting:

• May lead to dehydration if severe
• Often accompanied by nausea
• Can persist for several days
• May complicate the ability to maintain adequate fluid intake
• Can be particularly dangerous in children and elderly patients

The presence of vomiting, especially when combined with high fever and severe back pain, was historically considered a strong indicator of smallpox during the prodromal phase, before the characteristic rash appeared.

9. Extensive Scarring

One of the most lasting consequences of smallpox infection is the extensive scarring that occurs after the pustules heal. These scars, known as pockmarks, are permanent indentations in the skin that result from the deep-seated nature of the smallpox lesions.

The scarring process occurs because the pustules affect not just the surface of the skin but also the deeper dermal layers. When the scabs fall off, typically 2-3 weeks after the rash first appeared, they leave behind pitted scars. These scars are most noticeable on the face, where they can be numerous and disfiguring.

Characteristics of smallpox scarring:

• Deep, pitted appearance
• Permanent and do not fade significantly over time
• Most prominent on facial skin
• Can also appear on arms, legs, and other affected areas
• Number and severity correlate with the density of the original rash

The extensive scarring was one of the most feared aspects of smallpox, as survivors often bore visible lifelong reminders of their illness. The psychological and social impact of this disfigurement was significant in historical contexts.

10. Blindness and Eye Complications

Smallpox can cause serious eye complications, including blindness, which was one of the most devastating consequences of the disease. These complications occur when the pustules develop on or near the eyes, affecting the cornea and other delicate eye structures.

Eye involvement in smallpox can manifest in several ways:

Corneal lesions: Pustules can form on the cornea (the clear front surface of the eye), leading to scarring and opacity. Severe corneal scarring can result in partial or complete blindness in the affected eye.

Conjunctivitis: Inflammation of the conjunctiva (the membrane covering the white part of the eye) commonly occurs, causing redness, pain, and discharge.

Photophobia: Extreme sensitivity to light is common when the eyes are affected, causing significant discomfort.

Permanent vision loss: Depending on the severity and location of lesions, patients may experience:

• Complete blindness in one or both eyes
• Partial vision loss
• Clouded or distorted vision
• Chronic eye pain

Historical records indicate that smallpox was a leading cause of blindness before its eradication, with an estimated 1-3% of survivors experiencing severe vision impairment or complete blindness. The risk of eye complications was higher in cases with more severe and extensive rashes.

What Causes Smallpox?

Smallpox is caused by the variola virus, which belongs to the family of orthopoxviruses. Understanding the cause and transmission of this disease is essential for recognizing its serious nature.

The Variola Virus: There are two main strains of the variola virus:

• Variola major: The more severe form, with a mortality rate of approximately 30% in unvaccinated individuals
• Variola minor: A less severe form with a mortality rate of about 1%

Transmission Methods:

Smallpox spreads from person to person through several routes:

Direct contact: The virus can spread through direct, prolonged face-to-face contact with an infected person. Respiratory droplets expelled when an infected person coughs, sneezes, or talks can transmit the virus to others in close proximity.

Airborne transmission: In enclosed settings, the virus can remain suspended in the air for extended periods and infect people who share the same air space, even without direct contact with the infected person.

Contaminated objects: The virus can survive on clothing, bedding, and other materials that have been in contact with an infected person’s skin lesions or bodily fluids. Handling these contaminated items can lead to infection.

Infectious period: People with smallpox are most contagious during the first week of the rash, when the pustules in the mouth and throat release large amounts of virus. However, they remain contagious until all scabs have fallen off.

Risk factors for infection:

• Close contact with infected individuals
• Lack of vaccination
• Working in healthcare settings with infected patients
• Living in crowded or confined spaces
• Handling contaminated materials without proper protection

Prevention of Smallpox

Although smallpox has been eradicated globally since 1980, understanding prevention methods remains important for public health preparedness and historical knowledge.

Vaccination:

The smallpox vaccine is the most effective prevention method. Developed by Edward Jenner in 1796, the vaccine uses a live virus called vaccinia, which is related to but less dangerous than the variola virus. The vaccine:

• Provides immunity for 3-5 years with full protection
• Offers some level of protection for up to 10 years or longer
• Can prevent disease if given within 3-4 days of exposure
• Can lessen disease severity if given within 4-7 days of exposure

Current vaccination status: Routine smallpox vaccination was discontinued in most countries after the disease was eradicated. However, some governments maintain vaccine stockpiles and continue to vaccinate certain military personnel and laboratory workers who might be at risk of exposure.

Isolation and quarantine:

If smallpox were to re-emerge, strict isolation and quarantine measures would be essential:

• Immediate isolation of suspected or confirmed cases
• Quarantine of close contacts
• Use of negative pressure isolation rooms in healthcare facilities
• Restriction of movement for exposed individuals during the incubation period

Infection control practices:

• Use of personal protective equipment (PPE) including masks, gowns, and gloves
• Proper hand hygiene with soap and water or alcohol-based sanitizers
• Safe handling and disposal of contaminated materials
• Disinfection of surfaces and objects that may be contaminated
• Airborne precautions in healthcare settings

Public health measures:

• Surveillance systems to detect any re-emergence quickly
• Emergency response plans for potential outbreaks
• Maintenance of vaccine stockpiles
• Training of healthcare workers in recognition and management
• Public education about symptoms and transmission

Personal protective measures:

• Avoid contact with individuals showing symptoms of smallpox
• Do not handle clothing or bedding used by infected persons
• Maintain good overall health to support immune function
• Stay informed about public health announcements

Frequently Asked Questions

Is smallpox still a threat today?

Smallpox is considered eradicated globally, with the last natural case occurring in 1977 in Somalia. The World Health Organization declared smallpox eradicated in 1980. However, samples of the virus are kept in two secure laboratories in the United States and Russia for research purposes. The primary concern today is the theoretical possibility of the virus being used as a biological weapon or accidentally released from a laboratory.

How long does it take for smallpox symptoms to appear after exposure?

The incubation period for smallpox typically ranges from 7 to 17 days, with an average of 12-14 days. During this time, infected individuals have no symptoms and are not contagious. Symptoms begin suddenly with the prodromal phase, which includes fever, headache, and body aches, followed by the characteristic rash 2-4 days later.

How can you tell the difference between smallpox and chickenpox?

Several key differences distinguish smallpox from chickenpox. Smallpox lesions are more concentrated on the face and extremities, while chickenpox lesions are more numerous on the trunk. Smallpox lesions all progress at the same rate in a given area, appearing uniform, whereas chickenpox lesions appear in successive crops at different stages. Smallpox pustules are deep-seated and firm, while chickenpox blisters are superficial and soft. Additionally, smallpox causes severe prodromal symptoms including high fever and back pain before the rash appears.

Can smallpox be cured?

There is no specific cure for smallpox. Treatment is primarily supportive, focusing on keeping the patient comfortable, managing symptoms, preventing dehydration, and preventing secondary bacterial infections. If you suspect exposure to smallpox or any serious illness, seek immediate medical attention. Healthcare providers can offer supportive care and guidance, though any pharmaceutical interventions should only be taken under medical supervision.

Who is at highest risk for severe smallpox complications?

Unvaccinated individuals are at highest risk for contracting and experiencing severe smallpox. Additionally, pregnant women, infants, young children, elderly individuals, and people with weakened immune systems face increased risk of severe disease and complications. People with skin conditions such as eczema may also experience more severe manifestations of the rash.

How long does smallpox illness last?

The entire course of smallpox illness typically lasts 3-4 weeks from the onset of symptoms. The prodromal phase lasts 2-4 days, followed by the rash which progresses through its various stages over approximately 2-3 weeks. The scabs typically fall off by the third or fourth week. However, recovery and regaining strength may take additional weeks or months, and complications such as scarring and blindness are permanent.

Is the smallpox vaccine still available?

The smallpox vaccine is no longer routinely available to the general public in most countries since the disease was eradicated. However, governments maintain strategic stockpiles of the vaccine for emergency use. Some military personnel, laboratory workers who handle orthopoxviruses, and certain healthcare workers may still receive the vaccine. If smallpox were to re-emerge, vaccination campaigns would be implemented according to public health emergency protocols.

What should I do if I think I have been exposed to smallpox?

If you believe you have been exposed to smallpox, seek immediate medical attention and contact public health authorities. Isolate yourself from others to prevent potential spread. In the unlikely event of actual exposure, vaccination within 3-4 days can prevent disease, and vaccination within a week may reduce disease severity. Follow all instructions from healthcare providers and public health officials regarding quarantine, monitoring, and potential vaccination.

References:

• Centers for Disease Control and Prevention – Smallpox
• World Health Organization – Smallpox
• Mayo Clinic – Smallpox
• NHS – Smallpox
• MedlinePlus – Smallpox