Acute Dermatitis

The rashes discussed here are an acute form of dermatitis which appear suddenly and can last for days to weeks. The chronic rashes that are present for over 6 months typically fall into another category. These eruptions are described under their specific headings.

Eczematous Dermatitis

Those rashes that appear similar in nature to patients with atopic dermatitis are commonly referred to as an eczematous dermatitis. They are usually red and swollen, may sometimes blister, and are often itchy. The most common type is an irritant contact dermatitis, which often appears on areas exposed to the elements, soaps, detergents and sometimes solvents. Most commonly these rashes are evident on the hands, but can be seen anywhere on the body. In treating these, it is best to eliminate the use of harsh cleansers, toners or astringents.* We recommend non-soap cleansers such as Dove or Cetaphil and vigorous use of moisturizing creams or lotions.* The best products appear to be those with ceramides.* We commonly recommend Cerave cream and Cetphil Restoraderm lotion. In more severe cases topical steroid ointments and creams are useful.*

Allergic Contact Dermatitis

In the western United States allergic contact dermatitis to poison oak is common. The dermatitis is red, swollen, and often very itchy. It often appears in a linear distribution suggesting a casual contact by body movement. Occasionally this type of dermatitis can blister. A hot shower with soap and water will adequately wash the poison oak resin off the body.* Washing the clothes in hot water and detergent is recommended to prevent further exposure.* The treatment with antihistamines, potent topical steroids and sometimes a 2-3 week course of prednisone is indicated.*

In some individuals a red papular or bumpy dermatitis can appear on the trunk and extremities as a result of a drug reaction. These are usually seen in adult patients on multiple medications. The most common in our practice are the ace-inhibitors such as Lisinopril.* In children and adults antibiotic reactions especially from penicillins and sulfas can appear in a similar manner. Withdrawal of the offending agent is essential as well as the use of topical steroids and moisturizers.*

Pityriasis Rosea

There are acute conditions that appear much as psoriasis, a rash that is red and often scaly. Pityriasis rosea is the most common form of this type of rash. It appears as an annular patch that looks like ringworm and is commonly referred to as a herald patch. Later other similar areas appear on the trunk and extremities. Pityriasis rosea often spares sun-exposed areas. This condition lasts 6-12 weeks and will spontaneously resolve. The time frame and absence of future recurrence suggest that this condition is virally mediated. Non-soap cleansers, moisturizers and, sometimes, topical steroids are helpful.* Outdoor sunlight therapy, without burning is often the most helpful therapeutic agent.* It will often quickly induce a remission.*


Infections are a common cause of rashes and often appear fairly well localized to exposed areas such as the face, hands, or trunk. They often are painful and not itchy. Impetigo is the most common infection. It is particularly common on children’s faces, but can occur anywhere. It is characterized by an often weepy, crusted rash that spreads over a number of days. This most commonly is from staph aureus. While milder forms of this can be treated with topical agents such as mupirocin, most infections are best treated with an oral antibiotic that targets staph aureus. A red, pussy eruption that often takes the form of pimples on the trunk can be seen in patients who have recently used a hot tub. This is commonly referred to as hot tub dermatitis and results from pseudomonas aeruginosa. It is best treated by gentle cleansing and may require an oral antibiotic.*


A nodular often painful process that occurs in areas of infections is often referred to as an abscess. They often appear on the trunk, but can occur anywhere on the body. Oral antibiotics and surgical drainage are often required to clear these lesions.*

Fungal Infections

Finally, scaly annular or circular eruptions appearing on the hands, feet and groin are often caused by fungal infections of the skin. One commonly sees involvement of the web spaces in between the toes or discoloration of the toenails. These eruptions are best treated with antifungal agents after a skin scraping demonstrates the presence of fungal elements.*

In conclusion rashes can have multiple causes. These descriptions summarize the most common types of rashes encountered in daily life. However, there are many other conditions that are less common and can also cause rashes. These other conditions often require the expertise of a dermatologist for a diagnosis and treatment.

We treat all types of rashes in our Sacramento office.*  Please contact us via phone or the form on the left side of this web-page.