Everything to Know About Antibiotic Rash – Causes, Treatments, More

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Antibiotics can treat most bacterial infections and promote fast recovery. However, you might experience side effects when taking antibiotics. A common side effect is an antibiotic rash that most kids and adults experience as a reaction to the drug.

Drug allergy can happen to any, but you cannot ignore it since the allergy-related reaction can lead to severe consequences. Therefore, whenever you get an allergy-related reaction to your drug, stop taking it immediately and visit your doctor if the effects are lasting or worsening.

Your doctor might change your medication to make it safe and prevent complications. Keep reading if you want to know more about antibiotic allergies and rashes.

What Is an Antibiotic Rash?

An antibiotic rash is a rash that you can have if your immune system responds negatively to any components of antibiotics. Rashes are the reactions your skin might develop as a response to some medications. Most antibiotics will have a few side effects, including upset stomach, but some also cause rashes. We can take the example of amoxicillin and ampicillin. Both these cause rashes more compared to other antibiotics. Since both belong to the penicillin family, reactions to the drug will be more. Your doctor might inquire about penicillin allergy before prescribing this drug.

It is noteworthy that one in fifteen people experience some reaction when taking antibiotics. However, the drug reaction will be mild to moderate in most cases. You can get raised and itchy rashes on your skin, but that will resolve without treatment within hours to days.

Penicillin can cause the most allergic reaction, and you should take extra caution when considering this antibiotic. Around ten percent of people experience allergic effects after taking antibiotics from this family.

Is a Rash Common with Antibiotics?

No, the rash is not a common side effect of antibiotics. However, some antibiotics can cause rashes, and you can avoid them if you are allergic to them. Also, once you start taking a new antibiotic, you might get rashes. You can ignore the rashes if they are mild and resolve within hours. However, you will have to visit your doctor when the rashes develop a severe reaction, including itching and inflammation.

Most rashes might not be life-threatening, but it is better to take the opinion of health experts. In some cases, the rashes can be dangerous when not addressed immediately. You do not know which skin condition is mild and which one needs immediate medical attention. Therefore, you can talk to your doctor to avoid any complexities.

What Does Antibiotic Rash Look Like?

The antibiotic allergy rashes appear as a symmetrical outbreak of blotchy, red, and raised welts and spots. You might have the first appearance soon after taking your antibiotics. Also, some drug rashes will not cause other symptoms. However, some may have itching or tenderness that requires medical attention.

You might suspect medication impact if you get rashes immediately after having your antibiotics. First, check the appearance and other accompanying symptoms and then plan the treatment accordingly.

Antibiotic Skin Rash Picture

Antibiotic rash picture

Picture Credit: GPonline

Here are a few types of rashes you can get when taking antibiotics.

Exanthematous Rashes

These rashes account for around ninety percent of drug rashes. You will see small, flat, red, and raised skin, and some might have pus in them. These rashes appear on your trunk and back and then spread to other parts. Hives and maculopapular rashes are these types of rashes.

Hives are the red, itchy, and raised bumps that appear after taking the first or second dose of the antibiotic. It might happen due to a penicillin allergy. Since an amoxicillin rash might be dangerous, you should call your doctor when the drug reaction causes more harm.

Stop taking the antibiotics immediately and rush to the emergency when having breathing issues.

Swelling also warrants immediate medical attention. Some antibiotics can cause a severe reaction and life-threatening condition, and you can treat it soon after noticing any side effects to avoid any risk.

Maculopapular rashes look different from hives and will not appear soon after taking your antibiotic.

They look like red and flat patches on your skin, and you can also see paler and smaller patches with red patches. You can get this rash after taking your antibiotic for a few days. You can mostly have an amoxicillin rash, but you can also get this when taking other antibiotics.

Any penicillin allergy can lead to severe conditions and spread to the entire body. So when you notice such an appearance, you should pay attention to it, especially accompanied by other signs.

Urticarial Rashes

Urticarial rashes are the second most common type of rashes you can get after taking antibiotics. These rashes are also hives and appear as pale and small red bumps. You can see larger patches when having these rashes. However, these are itchy and more uncomfortable.

Photosensitivity Reactions

Some antibiotics can have negative impacts with sun contact. For example, they will make your skin extra sensitive to harmful UV rays, and you can get itchy sunburns if you explore outside without protective clothing.


These rashes are life-threatening and can make your entire skin red and itchy. Your skin will have scales within days if you ignore these rashes. You might also have a fever with these rashes. You should visit your health professional immediately if you have erythroderma.

Causes of Antibiotic Skin Rash

We get rashes on our bodies due to the allergic reaction caused by the drug. However, the response might be immediate or take time based on your immunity and the components in the medicines. In most cases, drug allergies cause rash or swelling. Both these conditions can be severe. But only rashes do not indicate that the person is sensitive to amoxicillin or similar antibiotics.

Also, your kid might not get rashes after taking an antibiotic for the first time. The immune system will respond well, and your kid will recover fast without experiencing any side effects. But a negative response might happen when using the same medicine for the second time. Rashes might appear on the skin of your kid. Hence, you cannot predict the impact of antibiotics on your kid. However, you can stop taking that drug and reach out to the doctor whenever you notice rashes or similar symptoms.

You can get rashes as an immediate and delayed reaction to medicines. You can get both by different pathways in your immune system. The immediate drug reaction or true allergies come from the protein antibodies activation that your body generates against medicine and can cause life-threatening conditions. You can experience this effect when taking IV medicines.

The delayed reactions or hypersensitivity response will come from immune cell activation. The response of the immune system to antibodies will cause this reaction. However, doctors cannot find the reason behind such a response.

Besides, a few factors can increase the risk of rashes and other side effects. For example, IV dosage will increase your risk compared to oral intake. In addition, the risk will be more when you take antibiotics for an extended period. Repeated exposure is another contributing factor. Also, females and older children will have more chances of developing rashes when taking penicillin antibiotics.

How to Treat the Antibiotic Skin Rash

The type and severity of the rashes will decide the treatment. Any reaction from antibiotics can cause fear, and most prefer to consult the doctor to avoid further deterioration. Yes, you can visit your doctor if the rashes spread fast all over the body and you also have swelling. Unfortunately, you cannot treat the condition with over-the-counter medicines when your kid is visibly ill and uncomfortable. However, you can treat the reaction of antibiotics with Benadryl when hives and rashes are not severe.

Stop the antibiotics right away regardless of the severity level of the reaction. When using over-the-counter medicines, follow the dosage instructions. Then, you can see your doctor to find a suitable alternative.

You can also treat itchy rashes with Benadryl. It is noteworthy that rashes might not be severe in most conditions. But allergy-related reactions can be life-threatening, and you can rule out this possibility by talking to your doctor.

When To See A Doctor

Drug rashes will disappear once you stop taking that antibiotic. The exact timeline will depend on the severity of the rashes. However, some rashes can cause lasting changes to skin pigmentation. You can talk to your doctor if the rashes have left permanent spots on your skin.

Frequently Asked Questions (FAQs)

You can decide your action based on the severity of the rashes. If the rashes are mild and resolve within hours, you can wait and talk to your doctor. However, you will have to rush to the medical when the rashes are severe and spread to other parts. Go to the emergency if your kid has breathing issues and gets swelling after taking the antibiotics. Again, you can plan your step based on the severity of the reaction to the drug. ​

​A rash might last for a few hours or a couple of days, depending on the type of antibiotics. Some rashes will resolve within an hour, and you will not experience any other effects. However, you will see rashes on the face, neck, back, and abdomen. Some rashes will last for more than a week, but you can act fast when you find them itchier and inflamed. ​

All the rashes from the amoxicillin will not behave in the same way. Your immunity system will decide how long the rashes will stay. But hives will appear within hours and might last more than weeks. Most rashes will go away once you stop taking medicine, but some might behave differently and get worse.

Talk to your health professional if you have yet to notice improvements within a week or two. 

​Yes, some get rashes when taking amoxicillin since this antibiotic belongs to the penicillin family and causes rashes in all age groups. Hence, you can have more rashes when taking this antibiotic. But it might not be an allergic reaction. Allergies will cause more complications than rashes. Allergies can spread fast and become life-threatening if you do not treat the condition immediately. 

You can get different types of rashes when taking antibiotics. Most will not have any other symptoms and will resolve within hours. But some antibiotics, including cephalosporins and penicillins, can cause allergic reactions. As a result, you can get raised and itchy rashes. However, you might not experience severe complications even with itchy rashes. They might disappear within days once you stop taking your drug.

The fastest way to treat antibiotic allergy rashes is to stop the medicine. Once you stop the drug, the hives and other rashes might disappear within hours. However, maculopapular rashes might take two weeks to go away completely. Also, they might worsen once you stop taking the antibiotic and take time to disappear. ​

Besides, you can consider using oral antihistamines when you have severe itching from the rashes. Topical steroids can also treat redness and itching. You can try any of these to treat your rashes and stop itching and irritation. However, it is better to consult your doctor to find an alternative medicine for your condition.

Hives that come immediately after having the medicine and spread fast might need immediate attention. You can get such reactions due to allergies. Some rashes also come later but pose the same risk. Hence, parents cannot understand whether they should visit a doctor or not. You can look for other symptoms when you suspect allergies.

Your kid might experience difficulty breathing, swelling on lips and face, wheezing, vomiting, and severe skin reactions accompanied by skin rashes. All these conditions will require medical attention.

You can act fast when your kid has a high temperature, skin pain or tenderness, or blistering. However, you do not need to worry if the rashes are mild and resolve within hours and when your kid does not have other symptoms.

An antibiotic skin rash might not be dangerous when caused by a reaction to the drug. However, it might lead to severe complications when caused by allergic reactions. Some allergens can cause life-threatening conditions for your kid, and you should never ignore them.

The content on Doctor Alexa’s blog is reviewed by Advanced practice registered nurses or pharmacist and is intended for educational purposes only. This information should not be relied upon as professional medical counsel. Be sure to always consult with your physician about the dangers and benefits of any medication, treatment or procedure.

You shouldn’t wait to see the doctor for simple health needs.