Rash Treatment in Petaluma & Hercules

Understanding Rashes

Rashes are one of the most common reasons patients visit our dermatology practice. Rashes can appear suddenly or develop gradually, and they may be itchy, painful, scaly, or simply red and unsightly. Because there are so many different types of rashes, it is important to have an accurate diagnosis from a board-certified dermatologist or an experienced dermatology PA. At Dermatology Associates of the Bay Area, we evaluate rashes every day.

Below are some of the more common types of rashes we see at our practice.

Eczema (Atopic Dermatitis)

Eczema is a chronic inflammatory skin condition that often begins in childhood but can affect people of all ages. It typically presents with dry, itchy, and inflamed patches of skin. The rash often appears on the face, neck, elbows, or behind the knees. Allergens, stress, weather changes, or irritants such as soaps and fragrances may trigger flare-ups.

Treatment often includes prescription creams, gentle skincare routines, and, in more severe cases, phototherapy or advanced biologic medications.

Contact Dermatitis

Contact dermatitis occurs when the skin reacts to a substance it touches. This can be irritant contact dermatitis (from harsh chemicals, detergents, or repeated hand-washing) or allergic contact dermatitis (from allergens like nickel, poison oak, or fragrances).

The rash typically looks red and inflamed, sometimes with blisters or crusting. Identifying and avoiding the trigger is crucial, along with the use of topical steroids or barrier creams to help calm inflammation.

Psoriasis

Psoriasis is an autoimmune condition that causes the skin to produce cells too quickly. The buildup creates thick, red, scaly patches that often appear on the scalp, elbows, knees, or lower back. Unlike many rashes, psoriasis tends to persist without treatment and may flare in cycles.

Modern treatments include topical medications, phototherapy, oral systemic agents, and highly effective biologic injections that target the immune system.

Rosacea

Rosacea is a chronic skin disorder that commonly affects the face, causing redness, visible blood vessels, and acne-like bumps. While not always thought of as a rash, rosacea often appears as persistent redness with flare-ups triggered by heat, alcohol, stress, or spicy foods.

Treatment may include topical or oral medications, laser therapy, and lifestyle modifications to avoid triggers.

Fungal Rashes

Fungal infections such as ringworm (tinea corporis), tinea versicolor, athlete’s foot (tinea pedis), and jock itch (tinea cruris) can cause red, itchy, ring-shaped rashes. These infections thrive in warm, moist environments and are contagious.

Treatment usually involves antifungal creams or oral medications for more resistant cases. Dermatologists can also distinguish fungal rashes from conditions that may look similar, such as eczema or psoriasis.

Bacterial Rashes

Certain bacterial infections, such as impetigo, can cause rashes that spread rapidly. Impetigo often begins with small blisters or sores that ooze and form a honey-colored crust, especially in children. Cellulitis is another bacterial infection that can cause a spreading red, warm, and tender rash requiring prompt medical attention. Folliculitis is an infection of the hair follicles. Abscesses are painful, pus-filled infections that require incision and drainage to help clear the infection.

These conditions usually need prescription antibiotics, either topical or oral.

Viral Rashes

Many viruses can cause skin eruptions, ranging from common childhood illnesses like chickenpox (varicella) and measles to shingles (zoster) in adults. Viral rashes often appear suddenly and may be accompanied by fever or other systemic symptoms. Shingles, in particular, causes a painful, blistering rash along one side of the body or face and requires prompt antiviral treatment (valacyclovir) to reduce the risk of complications.

Because viral rashes vary widely, a dermatologist’s exam is important for an accurate diagnosis.

Heat Rash (Miliaria)

Heat rash occurs when sweat ducts become blocked, trapping perspiration under the skin. It typically appears as tiny red bumps or blisters in areas prone to sweating, such as the chest, back, or skin folds. While often harmless and temporary, heat rash can be uncomfortable.

Cooling the skin, wearing lightweight clothing, and avoiding overheating usually help resolve the rash.

Hives (Urticaria)

Hives are raised, itchy welts that appear suddenly and may move around the body. They can be triggered by allergic reactions, medications (antibiotics), infections (UTIs, viral), or food (peanuts, eggs, shellfish). Acute hives usually resolve within hours or days, while chronic hives may persist for weeks or months.

Treatment may involve antihistamines such as Claritin or Zyrtec, or, in severe cases, prescription therapies that target the immune system.

Drug Reactions

Some medications can cause widespread rashes, ranging from mild redness to severe and potentially life-threatening conditions such as Stevens-Johnson syndrome. A new rash that develops after starting a medication should always be evaluated promptly by a physician.

Dermatologists can help distinguish between benign drug eruptions and severe reactions that need urgent care.

Other Common Rashes

Seborrheic Dermatitis (dandruff) – A flaky, oily rash often affecting the scalp, eyebrows, sides of the nose, and chest. It is thought to be caused by an overgrowth of a common skin yeast called Malassezia globosa.
Perioral Dermatitis – This is an acne-like rash typically on the lower face of women that is frequently confused with rosacea.
Granuloma Annulare – Is a common inflammatory rash that typically presents with pink-reddish bumps in a circle on the elbows and hands.
Pityriasis Rosea – Is a common rash in young adults that typically starts with a distinctive single patch on the trunk and is then followed by multiple similar but smaller patches in a Christmas-tree-like pattern.
Poison Oak – Found throughout the Bay Area, this plant contains a resin called urushiol that, in some people, triggers an intense allergic reaction.
Lichen Planus – An itchy, purple-colored rash that may also affect the mouth or nails.
Autoimmune Rashes – Conditions such as lupus can cause characteristic rashes, including the “butterfly” rash across the cheeks.
Infant Rashes – Babies commonly develop diaper rash, cradle cap, or viral exanthems, which may require dermatology expertise.
Scabies – is caused by a mite that burrows into the skin and is one of the itchiest rashes seen in our practice.

When to See a Dermatologist for a Rash

While some rashes are mild and self-limited, others signal underlying medical conditions or infections that require treatment. Seek medical care if a rash is:

Painful, blistering, or spreading rapidly
Associated with fever, chills, or feeling unwell
Not improving with over-the-counter treatments
Interfering with sleep, work, or quality of life

Dermatology Associates of the bay area doctors, pa, aesthetician, and staff. Group image outside.

Why Choose Dermatology Associates of the Bay Area?

Our team of board-certified dermatologists is dedicated to providing expert skin care for patients of all ages. At Dermatology Associates of the Bay Area, we combine advanced dermatology techniques with personalized care to help you achieve healthy, beautiful skin.

Choose a trusted dermatology practice committed to exceptional care and long-term skin health.

What sets us apart:

Board-Certified Dermatologists – Our dermatologists have completed rigorous training and certification to deliver the highest level of dermatologic care. Our medical colleagues recognize our expertise, and as such, we have been recipients of Castle Connolly Top Doctors – including most recently in January 2025
Comprehensive Skin Care – From medical dermatology and acne treatment to advanced acne scar solutions and cosmetic procedures, we offer a full range of services under one roof.
Patient-Focused Approach – Every treatment plan is customized to fit your unique skin type, concerns, and goals.
Advanced Technology – We use clinically proven treatments and devices for effective, safe results.

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Trusted by Thousands of Bay Area Patients

At Dermatology Associates of the Bay Area, our board-certified dermatologists and PAs are trained to recognize the subtle differences between rashes that may appear similar to the untrained eye. Early diagnosis can prevent complications, relieve discomfort, and restore healthy skin.

Rashes Treatment

Frequently Asked Questions

How do I know if my rash needs medical attention?

You should see a dermatologist if your rash is painful, spreading rapidly, blistering, or accompanied by fever or other systemic symptoms. Additionally, if over-the-counter treatments have not improved your rash after a week, or if the rash is interfering with your daily activities or sleep, it is time to seek professional evaluation. Our board-certified dermatologists can provide an accurate diagnosis and effective treatment plan.

What is the difference between eczema and psoriasis?

While both eczema and psoriasis can cause red, itchy, and inflamed skin, they are distinct conditions. Eczema typically appears as dry, irritated patches that may weep or crust, often triggered by allergens or irritants. Psoriasis is an autoimmune condition that causes thick, scaly plaques due to rapid skin cell turnover. A dermatologist can examine your skin and determine which condition you have, as treatment approaches differ significantly.

Can rashes be contagious?

Some rashes are contagious while others are not. Fungal infections like ringworm and athlete’s foot, bacterial infections such as impetigo, viral rashes like chickenpox and shingles, and scabies can all spread to others. However, conditions like eczema, psoriasis, and rosacea are not contagious. If you are unsure whether your rash can spread to family members or others, we recommend scheduling an evaluation.

How long does it typically take for a rash to clear up with treatment?

The timeline for rash resolution varies depending on the type and severity of the condition. Some rashes, like contact dermatitis, may improve within a few days of removing the trigger and using topical treatments. Fungal infections typically clear within two to four weeks with antifungal medication. Chronic conditions like eczema and psoriasis may require ongoing management, though symptoms can improve significantly with proper treatment. Your dermatologist will provide you with a realistic timeline based on your specific diagnosis.

What can I do at home to relieve rash symptoms while waiting for my appointment?

While waiting to see a dermatologist, you can take several steps to ease discomfort. Keep the affected area clean and dry, avoid scratching (which can worsen inflammation and lead to infection), apply cool compresses to reduce itching, and use fragrance-free moisturizers for dry rashes. Over-the-counter hydrocortisone cream may help with mild inflammation, and oral antihistamines can reduce itching. However, avoid applying any products if you suspect an allergic reaction, and seek immediate care if symptoms worsen.

Will my rash come back after treatment?

This depends on the underlying cause. Acute rashes caused by infections, allergic reactions, or temporary triggers often resolve completely with appropriate treatment and do not return. However, chronic conditions like eczema, psoriasis, and rosacea may require ongoing management to prevent flare-ups. Our dermatologists will work with you to develop a comprehensive treatment plan that not only addresses your current symptoms but also includes strategies to minimize future outbreaks.

Are there any tests needed to diagnose my rash?

In many cases, our experienced dermatologists can diagnose a rash through visual examination and discussion of your symptoms and medical history. However, some conditions may require additional testing. We may perform a skin scraping to check for fungal infections, a skin biopsy for unclear or persistent rashes, patch testing for suspected allergic contact dermatitis, or blood work for rashes that may indicate systemic conditions. Any necessary testing will be explained thoroughly before proceeding.

Does insurance cover rash treatment?

Most health insurance plans cover medically necessary dermatology visits and treatments for rashes, as these are considered medical rather than cosmetic concerns. Coverage typically includes the consultation, diagnostic procedures, and prescribed treatments. However, specific coverage can vary by insurance provider and plan. We recommend contacting your insurance company to verify your benefits, and our office staff is happy to assist with insurance questions and claims.