Maculopapular rash

A maculopapular rash is a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps. The term "maculopapular" is a compound: macules are small, flat discolored spots on the surface of the skin; and papules are small, raised bumps. It is also described as erythematous, or red. Dermatologists do not recommend the use of "maculopapular", preferring the use of "morbilliform" to describe such a rash.

This type of rash is common in several diseases and medical conditions, including scarlet fever, measles, rubella, secondary syphilis, erythrovirus (parvovirus B19), chikungunya (alphavirus), and heat rash. It is also a common manifestation of a skin reaction to the antibiotic amoxicillin or chemotherapy drugs. Cutaneous infiltration of leukemic cells may also have this appearance. Maculopapular rash is seen in graft-versus-host disease (GVHD) developed after a hematopoietic stem cell transplant (bone marrow transplant), which can be seen within one week or several weeks after the transplant. In the case of GVHD, the maculopapular rash may progress to a condition similar to toxic epidermal necrolysis. In addition, this is the type of rash that patients presenting with Ebola hemorrhagic (EBO-Z) fever will reveal. It is also seen in patients with Marburg hemorrhagic fever, a filovirus not unlike Ebola.

This type of rash can be as a result of large doses of niacin or no-flush niacin (2000 – 2500 mg), used for the management of low HDL cholesterol.

This type of rash can also be a symptom of Sea bather's eruption. This stinging, pruritic, maculopapular rash affects swimmers in some Atlantic locales (e.g., Florida, Caribbean, Long Island). It is caused by hypersensitivity to stings from the larvae of the sea anemone (e.g., Edwardsiella lineate) or the thimble jellyfish (Linuche unguiculata). The rash appears where the bathing suit contacts the skin. [See http://www.merckmanuals.com/professional/injuries_poisoning/bites_and_stings/marine_bites_and_stings.html]