What causes arm rash?

Arm rash may have many possible causes, including allergens (agents that cause allergies), infections, autoimmune disorders, or other causes, such as stress.

Allergic or inflammatory causes of arm rash

Arm rash may be caused by contact dermatitis. Common triggers include:

  • Cosmetics, dyes or detergents
  • Industrial chemicals, such as those found in elastic, latex and rubber
  • Metallic substances such as jewelry
  • Poison ivy or oak

Other allergic causes of arm rash include:

  • Eczema (skin disorder causing scaly or blistering rashes that may be caused by allergy)
  • Food allergies (allergic reactions to certain foods)
  • Insect bite allergy such as a bee sting

Infectious causes of arm rash

Arm rash can also be caused by infections including:

  • Eczema (skin disorder causing scaly or blistering rashes that may be caused by infection)
  • Erythema nodosum (red nodules under the skin associated with fever and other symptoms)
  • Impetigo
  • Lyme disease (inflammatory bacterial disease spread by tick bites)
  • Measles, mumps, rubella, roseola, and scarlet fever
  • Meningitis (infection or inflammation of the sac around the brain and spinal cord)
  • Pityriasis rosea (a rash resembling the shape of a pine tree)
  • Ringworm
  • Rocky Mountain spotted fever
  • Scabies
  • Strep throat (bacterial throat infection)

Autoimmune causes of arm rash

Arm rash can also be caused by autoimmune disorders including:

  • Kawasaki disease (rare, serious pediatric disorder characterized by inflammation of blood vessels, high fever, rash, and mucous membrane changes)
  • Psoriasis (thick scaly plaques sitting atop a reddened base)
  • Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues)

Other causes of arm rash

Arm rash can be caused by other conditions including:

  • Extreme cold or heat
  • Medications
  • Stress
  • Sunburn
  • Wearing close-fitting clothes for an extended period of time (occlusive dermatitis)

Serious or life-threatening causes of arm rash

In some cases, rash may be a symptom of a serious or life-threatening condition that should be evaluated immediately in an emergency setting. These include:

  • Allergic purpura
  • Anaphylaxis (life-threatening allergic reaction)

Questions for diagnosing the cause of arm rash

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your rash including:

  • When did the rash begin?
  • Are you taking any medications?
  • Did the rash start in one location and spread to another?
  • Does the rash cause any itching or scaling?
  • Do you feel otherwise healthy?
  • Have you tried any new products recently, such as soaps, perfumes, sprays or detergents?
  • Have you spent a lot of time outdoors lately?

What are the potential complications of arm rash?

Because arm rash may be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. For example, infectious diseases, such as mumps or measles, can lead to rare but serious complications, including miscarriage, hearing loss, and serious brain infections, such as encephalitis or meningitis. Lyme disease can progress to cognitive and functional impairments.

Once the underlying cause of your rash is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

  • Cognitive difficulties
  • Encephalitis (inflammation and swelling of the brain due to a viral infection or other causes)
  • Meningitis (inflammation or inflammation of the sac around the brain and spinal cord)
  • Miscarriage or stillbirth
  • Paralysis
  • Permanent hearing loss

Secondary infections, which may develop from scratching and related skin trauma


  1. Skin rashes and other changes. FamilyDoctor.org. http://familydoctor.org/online/famdocen/home/tools/symptom/545.html.
  2. Rashes. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/003220.htm.

What is arm rash?

Rash is a symptom that causes the affected area of skin to turn red and blotchy and to swell. A rash may cause spots that are bumpy, scaly, flaky, or filled with pus. Rashes can vary in location, pattern and extent and may occur in any area of the body. An arm rash can have a variety of causes, and it may indicate something occurring around the arm itself or suggest a systemic (body-wide) condi... Read more about arm rashintroduction


What other symptoms might occur with arm rash?

Arm rash may be accompanied by other symptoms, depending on the underlying disease, disorder or condition. Certain conditions that cause arm rash may also involve other body systems.

Related localized symptoms that may occur along with arm rash

Arm rash may be accompanied by other localized symptoms including:

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: May 7, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

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