Morbilliform

Morbilliform rash is a medical condition characterized by a widespread, erythematous rash that resembles the rash seen in measles. It is often referred to as "measles-like" due to its similarity in appearance. This type of rash is typically maculopapular, meaning it has both flat and raised components. Morbilliform rash is a common manifestation of drug reactions and viral infections.

Causes

The most common cause of a morbilliform rash is a reaction to medications. Drugs such as antibiotics (penicillins, sulfonamides), nonsteroidal anti-inflammatory drugs (NSAIDs), and anticonvulsants are frequently implicated. Besides drug reactions, viral infections, particularly those caused by Epstein-Barr virus, human herpesvirus 6 (HHV-6), and enteroviruses, can lead to the development of a morbilliform rash.

Symptoms

The primary symptom of a morbilliform rash is the appearance of red or pink spots that are flat or slightly raised. These spots typically start on the trunk and can spread to the limbs and neck. The rash is usually symmetrical and may be accompanied by itching. Fever and other systemic symptoms may be present, especially if the rash is due to an infectious cause.

Diagnosis

Diagnosis of a morbilliform rash is primarily clinical, based on the characteristic appearance of the rash and a history of drug intake or recent illness. Laboratory tests may be necessary to rule out specific causes, such as infections or systemic diseases. Skin biopsy is rarely needed but can be helpful in uncertain cases.

Treatment

The treatment of a morbilliform rash depends on its cause. If a drug reaction is suspected, discontinuing the offending medication is the first step. Symptomatic treatment may include antihistamines for itching and topical corticosteroids for inflammation. In cases of infection, treating the underlying infection is crucial. Supportive care, such as hydration and fever management, may also be necessary.

Prevention

Preventing morbilliform rash involves avoiding known triggers, such as specific medications in individuals with a history of drug reactions. Vaccination against common viral causes, like measles, can prevent rashes associated with these infections.