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If you’ve ever gotten a rash on a hot summer day, you may have experienced heat rash. Heat rash can happen to anyone and is uncomfortable. Let’s take a look at what causes heat rash and how to treat it at home and with medications.
What is heat rash?
Heat rash is a skin condition that happens when sweat ducts become blocked and sweat gets trapped beneath the skin. Heat rash, commonly known as "prickly heat" and medically known as "miliaria," is especially common during the summer when hot and humid weather trigger the condition. The most common heat rash symptoms are small red bumps, blisters, red lumps, itchiness, and prickly skin.
Heat rash is a very common type of heat illness that affects over 200,000 people every year in the United States. It occurs in infants, children, and adults. Other heat-related illnesses are heatstroke, heat exhaustion, and heat cramps. Heat rash is usually self-diagnosable and self-treatable with topical medications and home remedies.
How is heat rash diagnosed?
Heat rash is typically diagnosed by a physical exam. Newborns and infants commonly present with red bumpy rash on the face, neck, and trunk. Children and adults usually have a rash on the torso. The rash may feel rough like sandpaper. “Milder forms are marked by clear-fluid filled blisters and bumps, and more severe forms can be characterized by red bumps, itchiness or prickliness of the skin, and pus-filled bumps,” says Lili Barsky, MD, hospitalist at Healthcare Partners in Los Angeles. “Large flesh-covered bumps can result when the deepest skin layer is affected.”
Dr. Barsky goes on to say, “Infants are most susceptible as their sweat ducts are still immature, but heat rash can also appear in adults, most often where tight clothes cause friction, like in skin folds, armpits, elbow creases, or in the groin area. It can result from exposure to hot, humid climates, tightly fitting clothing, intense exercise or physical activity that leads to excessive perspiration, overheating, being overweight and even prolonged bed rest or febrile illness and certain psychotropic medications.”
A doctor or dermatologist may ask the following questions to help confirm a diagnosis:
- How long have you been experiencing these symptoms for?
- Does heat make your symptoms worse?
- How often do you get a skin rash like this?
Heat rash treatment options
Once you know you have heat rash, the next step is properly treating it. Most cases of heat rash will resolve on their own with the following practices:
- Cool off the skin with cool showers or baths
- Take an oatmeal bath or use baking soda in the tub
- Wear loose-fitting and cotton clothing to help keep the skin cool
- Use topical treatments like calamine lotion or topical steroids
- Avoid harsh soaps or cleansers and avoid scented lotions or beauty products
- Avoid adding certain ointments and petroleum jelly to the skin
If a heat rash lasts more than a few days, it may be time to seek medical attention. Heat rashes can turn into folliculitis, which is a condition where hair follicles become inflamed and infected. Heat rash may also turn into a more serious skin infection like cellulitis.
Heat rash isn’t a chronic condition. It can be successfully treated when it happens, and future flare-ups can sometimes be prevented. If you know you’re prone to heat rash and are about to be in warm weather, here are some things you can do to prepare:
- Rinse off the skin with cool clear water as soon as you get out of the heat.
- Avoid putting on creams, ointments, or sunscreens that contain mineral oil, petroleum, or other ingredients that can clog pores. Look for products that are noncomedogenic.
- Stay hydrated while avoiding alcoholic and caffeinated beverages.
Heat rash medications
Heat rash medications typically fall into a few categories—topical creams and OTC solutions.
Topical hydrocortisone
Topical creams that contain hydrocortisone help treat inflammation, which is why they’re good for heat rash. Hydrocortisone creams can be applied several times a day to the affected area, and most are available over-the-counter as hydrocortisone 1%. It is not recommended to use prescription strength steroids without seeing your healthcare provider first.
Over-the-counter therapies
Over-the-counter lotions like calamine lotion, oatmeal baths, or unscented oil free moisturizers can help soothe redness and itchiness that come with heat rash. These products are available at most drug stores.
What is the best medication for heat rash?
There isn’t one single heat rash medication that will work best for everyone. The best medication for you will depend on your individual symptoms, medical history, medications you’re already taking, and your response to treatment. Here are some of the most common heat rash medications.
| Best medications for heat rash | ||||
|---|---|---|---|---|
| Drug Name | Drug Class | Administration Route | Standard Dosage | Common Side Effects |
| 1% hydrocortisone cream (hydrocortisone maximum strength OTC) | Corticosteroid | Topical | Applied topically as directed on the package | Burning, itching, acne |
| Calamine | Antipruritic | Topical | Applied topically as directed on the package | Burning, itching, rash |
Dosage is determined by your doctor based on your medical condition, response to treatment, age, and weight. Other possible side effects exist. This is not a complete list.
What are the common side effects of heat rash medications?
Heat rash medications may cause some of the following side effects:
- Acne
- Itchy skin
- Burning skin
- Skin redness
Although it’s rare, some people have allergic reactions to heat rash medications that can cause difficulty breathing, hives, and swelling of the face or throat. You should seek immediate medical advice if you believe you’re having an allergic reaction.
This list of side effects is not complete. For a complete list of possible adverse events and drug interactions, talk with your doctor or another medical professional.
What is the best home remedy for heat rash?
Some natural remedies are effective at treating heat rash. Here are some that can easily be done at home:
Aloe vera
The aloe vera plant is well known for its soothing, cooling, anti-inflammatory, and antiseptic properties. If you have an aloe vera plant at home, you can cut open a leaf and apply the gel directly to your skin. If you don’t have a plant at home, aloe vera gel can easily be purchased at convenience stores.
Cold compresses
Cold compresses will help cool the skin down and stop any itching. Cold compresses should be wrapped in a towel or protective cover so that the skin doesn’t get burned from the cold temperature of the compress.
Oatmeal baths
Taking a cool bath with oatmeal can help relieve itching. Oatmeal has anti-itch and anti-inflammatory properties, which makes it great for heat rashes. Adding a cup or two of oatmeal to cool bath water will help your heat rash go away quicker.
When should you seek medical care for heat rash?
You should seek medical care for a heat rash if:
- You have any underlying medical conditions
- The rash persists more than 24 hours
- New rashes develop that look different from the initial rash or peeling skin
- You have signs of systemic illness: fatigue, muscle aches, headache, fever, vomiting, or diarrhea
- You have an adverse reaction to any tried treatments
- It's a child under 2 years old
Frequently asked questions about heat rash
What cures heat rash fast?
The best way to quickly cure heat rash (miliaria) is to cool down the skin with cool water. Getting out of hot weather or the hot environment that caused the rash in the first place will really help. Anti-itch and anti-inflammatory creams are also very helpful.
What does a heat rash look like?
A heat rash can appear on the chest, neck, groin, under the breasts, behind the knees, and in elbow creases. It looks like a red, blistery, or pimply rash.
What cream is good for heat rash?
Creams that contain the following ingredients are good for heat rash:
- Calamine
- Cortisone
- Lanolin
- Colloidal oatmeal
- Aloe vera
How do I treat heat rash?
Cool compresses, calamine lotion, aloe vera gel, and other topical creams like lanolin cream can help treat heat rash.
How long does it take for heat rash to go away?
Most cases of heat rash will completely go away within a few days. If you have a heat rash that lasts longer than this, it may be a good idea to contact your doctor.
Does heat rash spread?
Heat rash can spread all over the body but it isn’t contagious.
Can you get sick from heat rash?
It’s possible for severe cases of heat rash to become infected. Signs of an infection include pus draining from the affected area, fever, chills, and swollen lymph nodes. Infections can be serious and require medical attention.
Is coconut oil good for heat rash?
During a heat rash outbreak, applying coconut oil to the skin might not be the best idea because it could block sweat glands and cause the rash to worsen.
Is aloe vera good for heat rash?
Aloe vera is great to use for heat rash because of its cooling and soothing properties.
Is baby powder good for heat rash?
Baby powder can be good for heat rash because it absorbs perspiration and keeps it from collecting on the skin.
Does Benadryl help heat rash?
Benadryl can help treat heat rash because it’s an antihistamine, which can help stop itching and swelling.