Red Spots on Skin: Causes, Diagnosis, and Treatments

Red spots that appear on your skin can be caused by many different factors, including an infection, medical condition, skin irritation, or allergy. Some red spots go away on their own, but others may need treatment or medication to resolve them fully.

It can sometimes be difficult to determine exactly the underlying cause, which is why it's a good idea to get an accurate diagnosis from your doctor or dermatologist (a doctor who specializes in skin, hair, and nail conditions).

Causes of Red Spots on Skin

Heat Rash

Heat rash (or miliaria) happens when sweat glands are blocked under the skin, causing small, red, prickly bumps that can be itchy or painful. It usually appears in skin folds or areas where sweat accumulates, like the armpits, chest, back, arms, and groin.

Babies and people who live in hot climates, sweat a lot, or are on bed rest may be more prone to heat rash.

Treating heat rash involves keeping the area cool, dry, and irritation-free through home remedies such as taking cool baths or oatmeal baths, applying cool compresses, wearing loose clothing, and avoiding thick moisturizers.

Heat rash is usually not concerning and can resolve on its own in a few days, but it also has the potential to lead to secondary infection if not properly cared for. In severe cases, oral or topical antibiotics may be prescribed to help relieve the pain and discomfort.

Call your doctor immediately if you notice any signs of infection along with heat rash, including white or light coloring over the heat rash, flaking skin, pus oozing from the rash, or rash appearing on only one side of the body.

Cherry Angiomas

A cherry angioma (or cherry hemangioma) is a small, noncancerous skin growth that appears as a round red or purple spot made up of blood vessels. The bumps can be raised or flat and are common in adults age 30 and older. You'll often find cherry angiomas on the torso, but they can also develop on the arms, legs, and scalp.

Cherry angiomas are diagnosable with a visual examination and they typically don't require any treatment. That said, these spots can be removed noninvasively if their appearance bothers you or if they're repeatedly bleeding. Your doctor can recommend a relatively painless removal technique involving a laser, liquid nitrogen, or other methods.

It's not unusual for cherry angiomas to grow in size or occasionally bleed due to clothing or other irritation. Keep in mind that this is normal, and is typically not a cause for alarm.

Contact Dermatitis

Contact dermatitis is a common condition that happens when your skin comes into contact with something irritating or something that it's allergic to. It usually appears as an itchy red rash with bumps but can also include swollen or dry, cracked, flaky skin on any part of the body.

There are two main types of contact dermatitis:

Irritant contact dermatitis develops when the skin's protective barrier is weakened and the skin becomes irritated by a substance.
Allergic contact dermatitis develops when the immune system reacts against a chemical substance, causing the skin outbreak.

Sometimes, you'll know exactly what caused the contact dermatitis, like if you've come across poison ivy. But other times, it's not so clear. Your doctor may recommend a patch test to determine the causes of allergic contact dermatitis. Keep in mind that your skin can react to a product or substance even if you've used it previously without issues.

In many cases, contact dermatitis can clear up on its own in a few weeks, as long as you avoid the substance that caused it. Treatment will vary depending on what caused the reaction, but it can include over-the-counter hydrocortisone creams or prescription oral antihistamines.

If your contact dermatitis presents with symptoms of a severe allergic reaction—such as difficulty breathing or swelling of the mouth, lip, or throat—call your doctor right away or seek immediate urgent care.

Ringworm

Ringworm (tinea corporis) is a common fungal skin infection that causes a red, blotchy, circular rash with a raised edge. Sometimes ringworm can cause flaking and peeling, but it's typically not painful. It's often seen on the arms and legs, though ringworm can appear on any part of the body.

Ringworm is highly contagious and easily spread through skin-to-skin contact or contaminated objects and surfaces. Pets can also transmit the fungus.

It's typically diagnosed by a doctor based on its appearance and then treated with an over-the-counter or prescription topical antifungal cream. If it's not treated properly, ringworm can spread and may require an oral antifungal prescription.

Drug Rash

drug allergic reaction on leg — Cordelia Molloy / Science Photo Library / Getty Images

A drug rash occurs when your body has an allergic reaction to a topical, oral, or intravenous (IV) medication. Drug rashes can appear as hives (raised red bumps), a flat rash, a dark red or purple rash, scaly skin, or blisters. They can range from mild to severe, and in some cases, may require emergency medical attention.

To diagnose a drug rash, your doctor will want to review all medications and supplements you're currently taking. If the condition doesn't clear up after you stop using the medication in question, your doctor may prescribe other treatments such as corticosteroids or antihistamines to help reduce any uncomfortable or painful symptoms.

Allergic reactions can be serious and sometimes life-threatening. If a rash develops in the hours, days, or weeks after a new medication, contact your doctor immediately.

Pityriasis Rosea

Pityriasis rosea is a common, benign rash that usually happens in adolescents and young adults. It usually starts with one larger red spot on the chest, torso, or back, followed by smaller red spots with a ring-like shape. The spots can be scaly and itchy.

Experts don't know exactly what causes it, but it's believed to be linked to a viral or bacterial infection. Pityriasis rosea often happens after an infection and can come with symptoms such as headache, sore throat, and fever.

It's usually diagnosed by appearance, and sometimes disappears on its own in six to eight weeks. In some cases, your doctor may recommend a corticosteroid, antihistamine, or antiviral medication to help with itching and inflammation.

Blood Spots

Blood spots (or purpura) are red or purple-colored spots that crop up on the skin or inside the mouth in small or large patches. It happens when small blood vessels burst, causing blood to pool under the skin.

While they're generally not a cause for alarm, there's a possibility blood spots may indicate a more serious medical condition, like a blood clotting disorder. Your doctor will use an examination and blood and platelet count tests for diagnosis, and potentially prescribe a corticosteroid.

For severe cases, an IV medication or other prescription drugs may be recommended to treat low platelet count.

Atopic Dermatitis

atopic eczema on infant face — DermNet / CC BY-NC-ND

Atopic dermatitis is a common, chronic skin condition. It causes red, itchy, scaly, inflammatory rashes usually found in skin folds, such as the elbows, neck, wrists, and behind the knees or ears.

Atopic dermatitis is usually seen in children ages 5 and younger and is diagnosed by a doctor's physical exam. Treatment may include topical steroid creams (over-the-counter or prescription) and antihistamines or oral steroids for more severe cases. Experts also recommend keeping the skin well-moisturized to help reduce flare-ups.

Swimmer's Itch

Swimmer's itch (or cercarial dermatitis) is an itchy, bumpy, red rash that occurs after swimming in water contaminated with parasites known as schistosomes. They can be present in freshwater or marine habitats.

The rash typically develops within a day of exposure to the contaminated water and is not contagious. It's best treated with topical corticosteroids and oral antihistamines. It can occasionally require a doctor's visit for antibiotics if the infection doesn't go away.

Psoriasis

Psoriasis is an autoimmune skin disorder that can be triggered by stress, medication, infection, injury, or environmental factors. An itchy, irritated red rash with silvery plaques or scales—commonly on the elbows, knees, and scalp—forms when the immune system overproduces skin cells too quickly.

A doctor will be able to diagnose psoriasis by its appearance and occasionally a skin biopsy. Treatment will vary based on the severity of the condition and may include topical creams, immune suppressant medications, and UV light therapy. Cold compresses and oatmeal baths at home can also help reduce itching.

Lichen Planus

Lichen planus is an autoimmune condition that results in red spots on the inside of the mouth, nails, scalp, genitals, eyes, throat, and digestive tract. It typically appears as a flat, itchy, purple rash and is most commonly seen in women or people ages 30 to 60.

Lichen planus isn't contagious, and can either clear up on its own or become a chronic issue. Your doctor will be able to diagnose lichen planus with a physical examination and provide treatment options such as topical corticosteroids, topical retinoids, and oral antihistamines.

While the cause isn't fully understood, some experts suspect there could be a genetic component to the skin condition.

Petechiae

Petechiae are small red dots that look like a rash and often appear suddenly on the arms, legs, stomach, and buttocks. The spots usually don't itch and are not raised but can spread to different parts of the body and form larger patches.

Petechiae is actually not a condition but a symptom of a larger infection, trauma, bleeding disorder, or allergic reaction. Your doctor will conduct an exam to evaluate the underlying cause, with some of the most common being fungal, viral, or bacterial infections like those that cause the flu, strep throat, scarlet fever, and more.

Treatment will depend on the cause and may not be required if there's no sign of infection or spread. If you notice a fever with petechiae, it could indicate a serious infection that will require immediate medical attention from your doctor.

Pimples

Pimples are red spots on the skin, chest, and upper back that form when pores become blocked by oil and dead skin cells. When mixed with bacteria, the result is an irritated, inflamed, red bump.

Occasional, mild pimples can often be treated at home with over-the-counter acne products. People who experience pimples regularly may be diagnosed with acne vulgaris, or the more severe cystic acne, which will require the intervention of a dermatologist to treat.

Treatment options can range from topical products and oral antibiotics to isotretinoin, oral contraceptives for females, corticosteroid injections, or chemical peels.

When to See a Doctor

Determining whether the red spots on your skin will require a trip to the doctor will depend on the appearance and severity of the rash, your individual medical history, and any underlying conditions. But in general, red flag symptoms that indicate a possible infection include:

Fever
Fatigue
Trouble breathing
Severe pain or swelling
Pus oozing from the rash

Seek immediate medical care if any of the above symptoms accompany your red spots.

A Word From Verywell

Red spots on the skin are relatively common and are not always a cause for concern. But because the underlying causes vary greatly from infections to allergic reactions, parasites, or medical conditions, the only way to put your mind at ease is to get a correct diagnosis from your doctor.

Since red spots are a particularly visible symptom, you might consider a telemedicine appointment with a doctor or dermatologist. Video conferencing or providing digital photos of your rash can be an extremely convenient way for your doctor to check suspicious red spots on your skin and prescribe medication if necessary.