Q: Fever, full-body rash, itching, and hand blisters after enteritis. Pediatricians didn't mention chickenpox or HFMD. Could it be chickenpox or an allergy?

Medically reviewed by Sang Hyun Ahn, MD

This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.

Question:

Following suspected enteritis (stomach flu) symptoms, my child continues to have a fever and has developed a full-body rash with severe itching. Now, blisters are appearing on the back of their hands. We visited two pediatric clinics, but neither mentioned chickenpox or Hand, Foot, and Mouth Disease (HFMD). Given the itching and blisters, is there a possibility of chickenpox? Or could it be an allergic reaction?

Answer:

You must be very worried that a rash and blisters have developed after a bout of enteritis.

[Current Situation Summary]

• Full-body rash + itching + blisters on the back of the hands → Chickenpox, HFMD, a viral rash, and an allergic reaction are all possible.

• If the two pediatric clinics didn't diagnose chickenpox or HFMD → The rash pattern or the timing of its appearance might not have been typical during your visits.

[How to Distinguish: Chickenpox vs. HFMD vs. Allergy]

Chickenpox:

• The rash starts on the trunk and face, then spreads to the limbs.

• Progresses in stages: red spots → blisters → scabs.

• Multiple stages of these lesions are present at the same time.

• Can also appear inside the mouth and on the scalp.

• The rash typically starts 1–2 days after the fever begins.

Hand, Foot, and Mouth Disease (HFMD):

• Centered around the palms, soles, inside the mouth, and buttocks.

• More common on the palms than the back of the hands.

• Blisters are small and oval-shaped with a red surrounding area.

• Children often have difficulty eating or drinking due to mouth pain.

Allergy / Viral Rash:

• Itching is strong, but blisters are rare or absent entirely.

• Hives swell up and can change location within a few hours.

• Viral rashes are usually not itchy and do not involve blisters.

[What to Do at Home Right Now]

1. Take photos of the rash → Record changes over time (this is great for showing the doctor later).

2. Cut fingernails short and prevent scratching (to prevent secondary bacterial infections).

3. Wash lightly with lukewarm water and dress the child in breathable cotton clothes.

4. If the itching is severe → Call your pediatrician to ask if antihistamines can be administered.

5. If the fever is making the child uncomfortable → Give fever reducers (let me know if you need help checking the proper dosage).

[When to Seek Medical Attention Again]

If any of the following apply → Get a re-evaluation from a doctor today:

• Blisters increase rapidly in number or fill with pus.

• The child cannot even drink water due to severe mouth pain.

• Difficulty breathing or swelling of the lips/face (signs of a severe allergic reaction).

• Fever lasts more than 3 days, or the child becomes lethargic and slow to respond.

[If Chickenpox is Highly Likely]

• It is highly contagious → Stop attending daycare or school (until all blisters have fully scabbed over, which usually takes 5–7 days).

• Avoid contact with un-vaccinated family members or pregnant women.

• If confirmed as chickenpox → Antiviral medication (Acyclovir) can be considered (it is most effective when started within 24–48 hours of the rash onset).

[What to Ask the Doctor Next Time]

"Blisters have appeared on the back of the hands along with full-body itching. Is a re-evaluation for chickenpox or HFMD needed?"

"Would looking at the photos of the rash progression help with the diagnosis?"

"How do we determine if antihistamines or antiviral medications are necessary right now?"

For today, start by documenting the rash with photos and keeping the child from scratching.

For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.

https://fevercoach.us