Exanthem Rash Causes and Treatment

An exanthem rash is a skin rash that is widespread and often accompanied by fever, malaise, and other symptoms. Exanthem rashes are typically symmetric and red and may be flat (macules) or include small, raised bumps (papules).

Exanthems are usually caused by viral or bacterial infections such as measles and chickenpox. They can also be caused by drugs, toxins, or autoimmune diseases. The rash may or may not be itchy.

This article discusses exanthem rashes and what they look like. It also goes over causes and diagnosis.

What Is an Exanthem Rash?

An exanthem rash is a whole-body rash that may consist of flat, red patches or small raised bumps. Exanthems caused by viruses or bacteria often are part of systemic illness with fever, malaise, and headache. Some common diseases that cause exanthem rashes include measles, chickenpox, and rubella.

The skin rash is triggered by the body's reaction to a toxin produced by the infecting organism, or the immune response the body mounts to the organism or damage that the organism makes to the skin.

Diagnosing Exanthem Rashes

A sudden-appearing, widespread rash, especially with fever and malaise is cause for a visit to the doctor or urgent care clinic. Some causes need early treatment. Because of this course of the disease, exanthem rashes are often diagnosed by primary care physicians or urgent care providers.

Many exanthem rashes have a typical appearance that helps healthcare providers determine what disease or process is causing it.

It is part of medical training to recognize these rash patterns. Verification can include taking a swab for viral testing or PCR identification. Blood tests can be done to look for antibodies to specific viruses and bacteria. DNA probes can also identify suspected agents.

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What Causes Exanthem Rashes?

Exanthem rashes are associated with the following illnesses:

• Measles, specifically rubeola, caused by the measles morbillivirus
• Scarlet fever, which occurs after an infection of Streptococcus pyrogens (group A streptococcus). This can occur as a throat infection, strep throat
• Rubella or German measles, caused by the rubella virus
• "Dukes' disease" (probably a coxsackievirus or echovirus infection)
• Erythema infectiosum, caused by parvovirus B19, sometimes called "fifth disease"
• Roseola infantum, caused by herpesviruses HHV-6 and HHV-7

Exanthems used to be consecutively numbered based on their historical appearance and description. For example, measles was known as "first disease" and scarlet fever as "second disease."

Exanthems can also be caused by medication, especially beta-lactam and sulfonamide antibiotics and seizure medication. They may also be caused by toxins or autoimmune conditions.

Childhood Exanthems

Chickenpox (varicella-zoster virus), mumps, and the common cold are exanthems seen in children, as well as these from the classic list: measles, rubella, roseola, and erythema infectiosum. Many of these can be prevented by vaccines.

More Viral and Bacterial Exanthems

Viral exanthems beyond those listed include the human immunodeficiency virus (HIV) its acute infection stage. Smallpox (now eradicated) produced an exanthem. Viral hepatitis and infectious mononucleosis caused by the Epstein-Barr virus may produce an exanthem.

Bacterial infections producing a widespread rash include the big two, Staphylococcus toxin infections and Streptococcal toxin infections including toxic shock syndrome and scarlet fever.

Mycoplasma pneumonia, Kawasaki disease, and rickettsial diseases can cause these rashes.

How Do You Treat Exanthem Rash?

The treatment is based on treating the underlying disease, some of which are life-threatening but while others only need supportive care or are self-limiting. Treatment to reduce a fever is usually done. Creams such as hydrocortisone and calamine lotion may be given to reduce the itch if the rash is itchy.

Summary

Exanthem rashes are whole-body rashes that are usually associated with a viral or bacterial infection such as measles, rubella, and chickenpox. They may be flat rashes or they may present with small bumps called papules.

Treatment of exanthem rashes varies depending on the cause. Typically, the person with the rash will receive a fever-reducing treatment. Topical medication may be used to reduce itching.