rash

References

Images

skin rash caused by Lyme disease

Close-up of a person's torso showing a widespread red, blotchy rash characteristic of measles, with hands pulling up a green shirt to expose the skin.

rash

skin condition

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 22, 2026

Quick Summary

skin rash caused by Lyme disease — skin rash caused by Lyme disease Visible alterations in the texture of the skin, such as rashes and hives, can be indicative of serious disease. For example, one of the first signs of Lyme disease is a circular rash in a bull's-eye pattern on the skin.

A rash is a skin condition that can be caused by various factors, including infections, environmental agents, and internal diseases. The skin often reflects a person's overall health, making it the first organ to show signs of underlying conditions. Rashes can manifest in different ways depending on the cause and the specific area of the body affected.12

Skin diseases can stem from hereditary, inflammatory, neoplastic, endocrine, hormonal, traumatic, or degenerative processes. For instance, bacterial infections like impetigo or boils cause acute inflammation and pus, while fungal infections can lead to chronic eruptions. Viral infections, such as warts or shingles, also affect the skin. Infestations by mites, like in scabies, cause intense itching and allergic reactions. The distribution of a rash can be influenced by external factors like trauma or sunlight, or by internal factors such as nerve supply.1234

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

4 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

herpangina
…most distinctive symptom is a rash on the mucous membranes inside the mouth. The lesions in the mouth are round macules (non-raised spots) about 2 mm (0.1 inch) in diameter, occurring predominantly on the soft palate and tonsils. Herpangina is related to hand, foot, and mouth disease, which is caused…
Read More
…most distinctive symptom is a rash on the mucous membranes inside the mouth. The lesions in the mouth are round macules (non-raised spots) about 2 mm (0.1 inch) in diameter, occurring predominantly on the soft palate and tonsils. Herpangina is related to hand, foot, and mouth disease, which is caused…
Read More

Lyme disease
Symptoms and disease course
…is characterized by a circular rash in a bull’s-eye pattern that appears anywhere from a few days to a month after the tick bite. The rash is often accompanied by flulike symptoms, such as headache, fatigue, chills, loss of appetite, fever, and aching joints or muscles.
Read More
…is characterized by a circular rash in a bull’s-eye pattern that appears anywhere from a few days to a month after the tick bite. The rash is often accompanied by flulike symptoms, such as headache, fatigue, chills, loss of appetite, fever, and aching joints or muscles.
Read More

measles
Transmission and symptoms
…with appearance of a blotchy rash, and the temperature may rise as high as 40 °C (about 105 °F) when the rash reaches its maximum. Twenty-four to 36 hours before the rash develops, there appear in the mucous membranes of the mouth typical maculae, called Koplik spots—bluish white specks surrounded…
Read More
…with appearance of a blotchy rash, and the temperature may rise as high as 40 °C (about 105 °F) when the rash reaches its maximum. Twenty-four to 36 hours before the rash develops, there appear in the mucous membranes of the mouth typical maculae, called Koplik spots—bluish white specks surrounded…
Read More

Rocky Mountain spotted fever
A rash develops in the first week of illness, beginning on the extremities and spreading to the trunk. It is more profuse than the rash of epidemic typhus and affects the face as well as the body. In some people the colour of the rash deepens…
Read More
A rash develops in the first week of illness, beginning on the extremities and spreading to the trunk. It is more profuse than the rash of epidemic typhus and affects the face as well as the body. In some people the colour of the rash deepens…
Read More

scabies
In addition, a rash breaks out on parts of the body where there are no burrows—on the buttocks, over the shoulder blades, and on the abdomen. The rash is the result of an allergic reaction to mite proteins, feces, and eggs. It is intensely irritating and interferes with…
Read More
In addition, a rash breaks out on parts of the body where there are no burrows—on the buttocks, over the shoulder blades, and on the abdomen. The rash is the result of an allergic reaction to mite proteins, feces, and eggs. It is intensely irritating and interferes with…
Read More

scarlet fever
…because of the red skin rash that accompanies it.
Read More
…because of the red skin rash that accompanies it.
Read More

skin disease
Diagnosis
…modify the appearance of a rash. This is apparent when skin transplanted from one area of the body to another (other than a symmetrically opposite area) retains the morphological characteristics of the donor area. Thus the morphology of eczema or lichen planus on the palms and soles may bear little…
Read More
…modify the appearance of a rash. This is apparent when skin transplanted from one area of the body to another (other than a symmetrically opposite area) retains the morphological characteristics of the donor area. Thus the morphology of eczema or lichen planus on the palms and soles may bear little…
Read More

smallpox
The course of the disease
…the mouth and by a rash on the skin that was heaviest on the face and lower part of the limbs, displaying what was called a centrifugal, or centre-fleeing, distribution. The rash might be so profuse as to be confluent, especially on the face, or so scanty that the lesions…
Read More
…the mouth and by a rash on the skin that was heaviest on the face and lower part of the limbs, displaying what was called a centrifugal, or centre-fleeing, distribution. The rash might be so profuse as to be confluent, especially on the face, or so scanty that the lesions…
Read More