Shingles: Why the First 72 Hours Matter
Burning pain, tingling, or unusual skin sensitivity on one side of the trunk or face can begin before a rash appears. When grouped blisters develop in the same area a few days later, the cause may be shingles, also called herpes zoster. It is better not to wait for the rash to “fully develop”: antiviral treatment works best when it is started early.
What shingles is
Shingles is caused by varicella-zoster virus (VZV), the virus that causes chickenpox. After chickenpox, VZV remains inactive in nerve ganglia and can reactivate years later. It is not the same infection as herpes simplex caused by HSV-1 or HSV-2.
According to the World Health Organization, risk rises after age 50 and when the immune system is weakened. However, younger people can also develop shingles.
How to recognize the typical rash
Pain, itching, tingling, or numbness often starts in a limited area of skin. Spots and grouped blisters then appear. A typical shingles rash:
- is limited to one side of the body or face;
- forms a band along the area supplied by one nerve;
- usually does not cross the body’s midline;
- may be accompanied by burning or shooting pain, headache, fever, or feeling unwell.
Rash color varies with skin tone. Redness can be less obvious on darker skin, so the blisters, one-sided distribution, and character of the pain also matter. A rash on both sides, a widespread rash, or symptoms without the typical blisters need clinical assessment because another condition may be responsible.
Why the first 72 hours matter
The CDC says treatment is most effective within 72 hours of symptom onset. Acyclovir, valacyclovir, or famciclovir may be used for shingles. These medicines can speed lesion healing, reduce new lesions and viral shedding, and lessen acute pain.
A clinician should choose the medicine and regimen after considering age, kidney function, pregnancy, immune status, and other medicines. Using leftover antivirals or steroid eye drops without medical advice can be dangerous.
Three days is not a reason to stay home if more time has passed. Assessment still matters, especially if new blisters are appearing, the face is involved, pain is severe, or the immune system is weakened.
When urgent care is needed
Seek same-day medical care if the rash affects the forehead, nose, eyelid, or area around the eye. A red or painful eye, light sensitivity, blurred vision, or new floaters can signal eye involvement. Moorfields Eye Hospital advises prompt eye assessment because untreated disease can cause corneal inflammation, uveitis, and vision loss.
Urgent assessment is also needed for:
- ear pain or blisters, sudden weakness on one side of the face, hearing changes, or severe dizziness;
- a widespread rash, lesions in several separate areas, or rapid deterioration;
- substantial immune suppression from illness, chemotherapy, transplantation, or immunosuppressive medicines;
- pregnancy, or a suspected case in a baby or child;
- confusion, severe headache, a stiff neck, seizures, sudden limb weakness, or difficulty breathing — these require emergency care.
How the diagnosis is confirmed
Once a typical one-sided rash appears, shingles can often be diagnosed during an examination. If the presentation is unusual, the person is immunocompromised, or VZV must be distinguished from herpes simplex, the most useful confirmatory test is PCR performed on material from a blister, scab, or the base of a lesion. The CDC notes that blood IgM testing is less sensitive and cannot reliably distinguish primary infection from reactivation.
What you can do at home
- Keep the rash clean and dry and wear loose clothing.
- Cover blisters with loose clothing or a non-stick dressing.
- Wash your hands after touching the area and avoid scratching.
- Ask a clinician or pharmacist about safe pain relief, particularly if you have kidney disease, ulcers, take anticoagulants, or are pregnant.
You cannot “catch shingles” from someone with shingles. However, until all blisters have crusted, VZV can cause chickenpox in a person who has never had chickenpox and has not been vaccinated. During this period, avoid contact with newborns, pregnant people without immunity to chickenpox, and people with substantially weakened immune systems. The NHS also provides practical advice on rash care and contacts.
Pain after the rash has gone
The most common complication is postherpetic neuralgia: nerve pain that continues after the skin has healed. The CDC estimates that it affects about 10% to 18% of people with shingles, with risk increasing with age. If pain disrupts sleep or daily activities, speak with a clinician; nerve pain may require specific treatment. Read more in our guide to postherpetic neuralgia.
Can another episode be prevented?
Recombinant shingles vaccine reduces the risk of shingles and postherpetic neuralgia. Recommended ages, availability, and schedules vary by country and immune status. Discuss vaccination with a clinician even after a previous episode because shingles can recur.
Sources
- WHO: Shingles (herpes zoster)
- CDC: Clinical Overview of Shingles
- CDC: Shingles Symptoms and Complications
- CDC: Laboratory Testing for VZV
- Moorfields Eye Hospital: Ocular shingles
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