A maculopapular rash is distinctive but not definitive — it can indicate many conditions. This type of skin rash is characterized by a flat, red area that is usually dry and covered in small bumps. Maculopapular rashes are common in children, but they can affect people of any age and can appear anywhere on the body.

Appearance

Maculopapular rashes are a combinaton of macules and papules. Macules are flat, red regions of up to about a centimeter that lie flush with the skin. Papules are reddened lesions of up to a centimeter that are slightly elevated. If these lesions are close together, they can merge. Macules that merge are called patches, and papules that merge are called plaques.

Location

Where on the body a maculopapular rash develops depends, to some extent, on the cause. In some cases, the rash is central, affecting the trunk and not the arms and legs. Some causes of maculopapular rashes have specific patterns and locations and progress in a way unique to that cause. In some cases, the affected area and location of the rash help doctors obtain or confirm a diagnosis.

Measles

Measles is an infection commonly linked to a maculopapular rash. The rash starts behind the ears, then progresses to the front of the face. Over the next few days, it moves down to the neck, torso, arms, and legs. One of the identifiable characteristics of measles is that the rash stops evolving when the fever resolves. It disappears in the same way it developed, fading first from the face.

Rubella

Rubella is another infection that presents with a recognizable maculopapular rash. Between 50 and 75 percent of people with rubella have symptoms, and a red rash is often the first sign. It typically starts on the face and spreads to the rest of the body, resolving in about three days. Rubella is more common in children than adults and not as prevalent as it once was since most babies receive the MMR vaccine that inoculates against measles, mumps, and rubella.

Pityriasis Rosea

Pityriasis rosea is a maculopapular rash that typically develops in children and young adults. Experts suspect many causes of pityriasis rosea but have yet to definitively link it with any virus or bacteria. Pityriasis rosea usually begins with a herald patch — a large, ring-shaped lesion that appears about a week before clusters of smaller lesions. This rash can be very itchy, and it is usually self-limiting, meaning it will go away without treatment.

Scarlet Fever

Another cause of a maculopapular rash is scarlet fever, a mild infection of group A strep. A red rash usually appears a few days before other symptoms, but it may appear up to a week afterward. The rash can develop on the neck, under the arms, and in the groin. It usually starts as small, flat, red areas and evolves into fine bumps.

Drug Reactions

Drug reactions are another common cause of maculopapular rashes. The rash most commonly occurs because of an allergy, sensitivity, or unwanted side effect. Timing, location, and severity vary depending on the person and the medication. Any drug can cause a maculopapular rash, but common culprits include antihypertensives, antibiotics, and contrast dyes.

Diagnosis and Treatment

Maculopapular rashes are common in children, but they can appear in people of all ages. To diagnose the cause of a rash, the physician takes a thorough history that includes how long the rash has been present, how it developed and spread, whether it evolved, where it appeared, and what treatments the patient has tried. The doctor will also take note of any other symptoms the patient may have, such as a fever or itching. Treatment varies depending on the cause and often consists of a cream or antibiotic.

When to See a Doctor

Some rashes are easily treatable, but others indicate a more serious problem. See a doctor if the rash has spread across the whole body or if a fever develops. Rashes that come on suddenly and spread quickly could be the result of an allergy. Anyone who experiences difficultly breathing after the development of a rash should seek immediate medical attention.

Complications

Some complications can arise from a maculopapular rash. Itchy rashes are at risk for infection if the skin breaks open from scratching. Signs of an infection include pain, warmth, yellow or green fluid, or a red streak coming from the rash. If blisters or open sores appear without scratching, the rash may be the result of a more serious ailment and should be examined by a doctor. Painful rashes also require fast evaluation.