Skin rashes have many causes, from allergies and irritants to infections and long-term skin conditions. This guide compares eight common skin rashes by how they look, where they start and what helps. It also explains the warning signs that mean you should not wait.
Written and fact-checked by the HealthCoachJP editorial team. No clinician has reviewed this article. See our sources and standards.
Quick Answer
Most skin rashes settle with gentle care and by avoiding the trigger. Get emergency help for a rash that looks like small bruises and does not fade under a pressed glass. Also seek help for any rash with trouble breathing, lip or throat swelling, a stiff neck or confusion. Rashes with fever, such as measles, chickenpox and scarlet fever, need medical advice.
What Causes Skin Rashes
A rash is a change in the skin’s color, texture or feel. It can be dry, wet, bumpy, smooth, cracked or blistered. Besides that, it may itch, sting or hurt. It can cover a small patch or most of the body.
Common causes include contact with irritants or allergens, medicines, infections and immune-related conditions. For example, soaps, detergents, heat and stress can trigger eczema. Likewise, insect bites can cause itchy bumps, so see our guide to bed bug and mosquito bites. In contrast, psoriasis involves the immune system, not an allergy.
Some medicines cause a rash as a side effect or an allergic reaction. If a rash starts after a new medicine, call your prescriber or pharmacist. Do not stop prescribed medication on your own.
Skin Rashes Compared: Timing, Location and Clues
Where a rash starts and how it changes often narrows down the cause. Therefore, the table summarizes NHS, CDC and American Academy of Dermatology descriptions.
| Rash | Where it starts | Key clue |
|---|---|---|
| Measles | Face and behind the ears, then downward | Follows cold-like symptoms and fever; usually not itchy |
| Rubella | Face, then the rest of the body | Serious in pregnancy because of congenital rubella syndrome |
| Chickenpox | Spreads across the body | Itchy spots turn to blisters, then scabs |
| Scarlet fever | Chest and tummy | Sandpaper feel 12 to 48 hours after flu-like symptoms; strawberry tongue |
| Impetigo | Around the nose, mouth and hands | Sores burst and leave golden-brown crusts |
| Heat rash | Skin that sweats or rubs | Small, itchy, prickly raised spots; not contagious |
| Hives | Anywhere | Each welt fades within 24 hours, but new ones can appear |
| Kawasaki disease | Varies | Fever of 5 days or more, red eyes, cracked lips; mostly children under 5 |
Skin Rashes That Need Urgent Help
The NHS describes a simple glass test. Press a clear glass against the rash. If small bruise-like spots do not fade, treat it as an emergency and call 999 or go to A&E. In the US, call 911 or go to the nearest emergency room.
Also seek emergency care if a rash comes with any of these signs:
- Difficulty breathing, or sudden swelling of the lips, mouth, throat or tongue.
- A stiff neck, sensitivity to light, or confusion.
- Pale, blue, grey or blotchy skin.
- A rash with unexplained bleeding or bruising, or a high fever that does not settle.
On brown and black skin, a rash can be harder to see. The NHS advises checking the palms, soles, lips, tongue and inside the eyelids.
8 Common Skin Rashes Explained
1. Eczema
Eczema causes dry, red, itchy skin that can crack or ooze. It is not contagious. According to the NHS, triggers include soap, detergents, heat, skin infections and stress. A short course of 1% steroid cream may help, so read our guide to hydrocortisone cream. For specific sites, see eczema on the lips and ear eczema.
2. Chickenpox
Chickenpox causes an itchy rash that moves from spots to blisters to scabs. Importantly, people are contagious from one to two days before the rash appears until every lesion has crusted. The CDC recommends two doses of varicella vaccine.
For fever, the CDC recommends acetaminophen (paracetamol in the UK). Avoid aspirin in children because of the link to Reye’s syndrome. The American Academy of Pediatrics also advises avoiding ibuprofen if possible. It has been linked to serious bacterial skin infections. Meanwhile, calamine lotion or an oatmeal bath can ease itching. Do not use hydrocortisone cream, because the NHS lists chickenpox as a reason to avoid it.
3. Rubella
Rubella, or German measles, causes a red rash that starts on the face and spreads. The CDC says it is no longer endemic in the United States, but it still circulates elsewhere. The main danger is to pregnancy. Infection can cause miscarriage or congenital rubella syndrome, which can affect almost every part of a developing baby’s body. Anyone who is pregnant and may have been exposed should contact their clinician.
4. Hives
Hives are raised, itchy bumps or patches that vary in size and shape. The AAD says individual hives go away within 24 hours, although new ones can appear. Hives lasting six weeks or longer on most days are called chronic. A non-drowsy antihistamine is a common first choice. For triggers, see our stress rash guide.
5. Prickly Heat
Heat rash shows up as small, raised, itchy or prickly spots with mild swelling. It is not contagious. To ease it, the NHS advises keeping the skin cool and avoiding scratching.
6. Intertrigo
Intertrigo is a red, sore rash in skin folds, such as the groin, armpits and under the breasts. Friction and trapped moisture damage the skin, and yeast or bacteria can then move in. Germany’s public health portal lists diabetes, overweight, heavy sweating and a weakened immune system as risk factors. Keeping folds clean and dry is the main treatment. Infections need an antifungal or antibiotic.
7. Impetigo
Impetigo is a contagious bacterial infection. Red sores or blisters burst and leave golden-brown crusts, usually around the nose, mouth and hands. Treatment is hydrogen peroxide cream or antibiotics, according to the NHS. With treatment, people stop being contagious 48 hours after starting. Finally, finish the full course.
8. Psoriasis
Psoriasis causes thick, scaly patches because skin cells build up faster than normal. It is not contagious and cannot be cured, but treatments control it. The NHS lists stress, alcohol, smoking, obesity and some infections as triggers. However, some people develop psoriatic arthritis, so see a doctor if joints become painful or swollen.
How common is it? Published US figures differ. CDC researchers estimate 3.1% of adults, about 6.7 million, from national survey data collected in 2003 to 2010. In contrast, the National Psoriasis Foundation cites 3.0%, or more than 7.5 million. Because the CDC number extrapolates from adults aged 20 to 59, treat both as estimates.
Skin Rashes: Claims and Where They Stand
| Claim | Where it stands | Reader guidance |
|---|---|---|
| Ibuprofen is a good fever reducer for chickenpox | Overstated | The AAP advises avoiding it if possible; use acetaminophen |
| Measles causes itchy bumps | Not supported | The NHS says the measles rash is usually not itchy |
| Rubella has been wiped out | Overstated | Not endemic in the US, but still present elsewhere |
| Hydrocortisone helps any rash | Not supported | Avoid it with chickenpox, shingles, acne and skin infections |
| A bruise-like rash can wait | Not supported | If it does not fade under a glass, seek emergency care |
| Psoriasis affects 7.5 million US adults | Estimates vary | CDC says about 6.7 million; the foundation says over 7.5 million |
When to See a Doctor About Skin Rashes
Beyond the emergency signs above, book an appointment if a rash lasts more than a few days or keeps returning. Also see a doctor if it spreads or interferes with sleep. Redness, warmth, pus or increasing pain can signal infection. Rashes with fever in babies need prompt advice. For more skin concerns, read about raised white spots, fungal acne and dry itchy scalp.
Frequently Asked Questions About Skin Rashes
Eczema, hives, heat rash, impetigo and psoriasis are among the most common. Infections such as chickenpox, measles and scarlet fever also cause rashes, especially in children.
Press a clear glass firmly on the rash. If the spots do not fade, they may be bleeding under the skin. The NHS says to call 999 or go to A and E straight away.
It depends on the cause. Chickenpox, measles, rubella and impetigo spread between people. Eczema, psoriasis and heat rash do not.
No. The NHS says to avoid it with acne, cold sores, bacterial infections, chickenpox and shingles. Over-the-counter use is limited to about seven days.
The CDC recommends acetaminophen. Avoid aspirin because of Reye’s syndrome. The American Academy of Pediatrics advises avoiding ibuprofen if possible.
The AAD says individual hives go away within 24 hours, though new ones can appear. Hives lasting six weeks or longer on most days are called chronic.
Usually not, according to the NHS. It is a blotchy rash that starts on the face and behind the ears after cold-like symptoms and fever.
Friction and trapped moisture irritate the skin, and yeast or bacteria can follow. This is called intertrigo. Keeping the fold dry is the main treatment.
Seek urgent help for a rash that does not fade under a glass. Do the same for a stiff neck, trouble breathing, confusion or a high fever. Call a doctor for any rash with fever in a baby.
Related Reading
- Hydrocortisone cream 2.5%: uses, risks and safe use
- Stress rash on the face and hands: causes and treatment
- Difference between bed bug bites and mosquito bites
- Eczema on the lips: causes of allergic reactions
Sources
- CDC: How to treat chickenpox
- American Academy of Dermatology: Hives
- CDC: Prevalence of psoriasis among adults in the US
- National Psoriasis Foundation: Prevalence of psoriasis
- gesund.bund.de: Intertrigo
- NHS: Hydrocortisone skin cream
- NHS: Rashes in babies and children; Hives; Atopic eczema causes; Psoriasis; Impetigo; Kawasaki disease. CDC: Measles signs and symptoms; Chickenpox clinical overview; Rubella (plain-text citations)
Disclaimer: This article is for general information and is not medical advice. A rash can have many causes, so see a doctor for a diagnosis. Seek emergency care for the warning signs above.
Last reviewed and rewritten October 2026.
