What Are the Most Common Causes of Morbilliform Rashes?

Morbilliform rashes are types of rashes that resemble an outbreak of the measles. The most common causes of these skin rashes are drug interactions, viruses, and bacterial infections. Interactions with drugs are often delayed, occurring one or two weeks after the drug is in a person’s system, and are due to a sensitivity or allergic reaction. Viruses can cause a wide variety of symptoms, including a morbilliform rash. Bacterial infections, such as those that occur from a streptococcus infection, can lead to a rash as well.

A morbilliform rash is a type of maculopapular rash that appears on the skin. The eruptions are red colored and raised above skin level. Eruptions are often small, resembling pimples. They can be warm to the touch, itchy, and painful, depending on their location on the body.

Drug interactions are one of the common causes of these rashes. The rash occurs because the body either cannot process the medication properly or is sensitive and develops an allergic reaction. A reaction most commonly occurs after beginning treatment with antibiotic medications. Adults most often suffer from rashes due to a drug reaction because the body cannot tolerate the introduction of foreign materials. In many cases, a rash occurs from a drug reaction due to a conflict with other medications that results in a sensitivity developing that did not previously exist.

Morbilliform rashes can also be caused by a virus. In children, rashes that develop from viral infections are common. The virus can usually be identified. Roseola and rubella are viral diseases that are commonly identified in children. With rashes in adults with viral infections, the virus cannot usually be identified and the rash is called a non-specific viral morbilliform rash.

Bacterial causes are another possibility. Exposure to bacteria causes the immune system to respond. One of the symptoms that is possible with bacterial infections is a morbilliform rash. The body is exposed to the bacteria, the immune system tries to defend the body, and a wide variety of symptoms occurs. This type of rash often occurs on the chest or arms first and can spread further as the body continues to defend against the bacterial invasion.

Treatments for morbilliform rashes differ. The underlying cause of the rash must be identified and treated. Many doctors combine treatments for the condition, causing the rash and treatments to ease the symptoms of the rash as well. Corticosteroids, in oral or topical forms, are effective in reducing inflammation and itching. Antihistamines are also commonly used to treat these rashes.