Not all rashes are created equal
A rash that comes out of nowhere can be alarming. Some rashes may not be that big of a deal, while others may indicate a serious health concern.
Rashes develop for many reasons. Some common causes include:
- Allergic reactions: Skin contact with allergens, such as poison ivy, certain metals or fragrances, can trigger rashes like contact dermatitis.
- Viral infections: Viruses, such as measles, chickenpox or hand, foot and mouth disease, often cause distinctive rashes.
- Bacterial infections: Conditions, such as impetigo or scarlet fever, result from bacterial infections that require medical treatment.
- Fungal infections: Athlete’s foot and ringworm are examples of rashes caused by fungi.
- Autoimmune diseases: Chronic conditions, such as lupus or psoriasis, can cause persistent rashes due to your immune system not working properly.
- Heat or irritation: Heat and diaper rash occur when sweat or moisture gets trapped against the skin, leading to irritation.
“Serious health conditions that can cause rashes include lupus, dermatomyositis, infections, medication reactions or lymphoma,” says Dr. Linda Serrano, a dermatologist at Aurora Health Care. “These may have accompanying fevers, lymphadenopathy, pain, facial swelling, full body redness, hand and feet involvement, oral involvement or scalp involvement.”
A rash located in or around your eyes, genitals or mouth may also indicate a serious issue.
Rash appearance
Not all rashes look the same. Some appear as red, itchy patches, while others may blister, scale or cause pain.
For example, eczema is a chronic condition that causes dry, itchy and inflamed skin. It’s common in children and often linked to allergies or asthma.
Hives are raised, itchy welts that can appear suddenly. They are also linked to allergies but can be caused by stress or infections.
Some conditions, such as shingles and rosacea, can also cause rashes to develop. Shingles is a painful rash with blisters caused by the reactivation of the chicken pox virus in older adults or people with weakened immune systems.
Rosacea is a long-term condition that causes skin redness and visible blood vessels, often affecting the face.
When to seek medical attention
While many rashes are harmless and improve with over-the-counter treatments, some require evaluation by a health care provider. Seek medical attention if:
- The rash is widespread or spreading rapidly
- It’s accompanied by fever, pain or difficulty breathing
- You notice blisters, open sores or signs of infection, like pus and swelling
- The rash doesn’t improve with home treatment or keeps coming back
- It appears after taking a new medication
Once your health care provider determines the cause of your rash, they will put you on a treatment plan that may include antihistamines, corticosteroid creams or soothing oatmeal baths. Bacterial and fungal infections may require prescription antibiotics or antifungal medications.
“Gentle skin care is key for treating and preventing flareups of many chronic skin conditions,” Dr. Serrano says. “This includes using fragrance-free soaps, washes and moisturizing creams daily. Sun protection is also vital to preventing rash flareups. I also recommend avoiding botanical products as these have natural irritants.”
She also advises having regular dermatology or primary care visits to help assess disease activity and always using medications as prescribed.
