Causes of Rash

There are many causes of rash. So many that it’s hard to list them all!

Simple Causes: There are many simple causes of a rash or rash-like skin conditions.

  • Skin irritation (e.g. from scratching)
  • Contact Dermatitis
  • Allergic reaction
  • Acne
  • Rosacea
  • Heat Stress (Excessive Exercise)
  • Heat rash (“prickly heat”)
  • Diaper rash

Skin Complaints: Some common skin conditions include:

  • Skin wound
  • Hives (urticaria)
  • Warts
  • Boils
  • Furuncles
  • Skin ulcer
  • Sebaceous cysts (skin cysts)
  • Millium (sweat gland cyst)
  • Birth marks
  • Port wine stain
  • Sturge-Weber syndrome (a condition with port wine stains)

Contagious Infection Causes: There are many different infections that can lead to a rash.

Rash Causes: Some of the other causes of rash include:

Non-Infectious Systemic Conditions: Various systemic conditions may cause rash:

Pustular Rash: Some of the causes of a Pustular Rash include:

Bullous Rash (Blistering Rash): Various causes of a bullous rash with blisters or bullae include:

Skin Ulcers: There are various causes of skin ulcers or an ulcerative skin rash:

Butterfly Rash: Causes of a “Butterfly Rash” across nose and cheeks:

  • Lupus (SLE)
  • Rosacea
  • Discoid Lupus Erythematosus
  • Seborrheic dermatitis
  • Polymorphous light eruption
  • Erysipelas
  • Erythema Infectiosum
  • Parvovirus (slap-cheek syndrome; fifth disease)
  • Drug reaction.
  • Photosensitizing drugs

Larger Circular Rash: Disorders that cause a distinctly circular-shaped rash or circular redness areas that are larger than small circular lesions (e.g. pustules, pimples, red spots, etc.), may include:

Bullseye Rash (Target Rash): Causes of a bullseye rash (a target-shaped rash) with a central redness area and concentric red circular rings include:

  • Lyme disease (centralized over the tick bite location)
  • Southern Tick Associated Rash Illness (STARI)
  • Erythema multiforme
  • Erythema annulare centrifugum (EAC)

Radiating Rash: A rash with a central point and radiating lines of redness may be indicative of:

One-Sided Rash: A local rash is obviously small and on a single side of the body. The occurrence of a non-local rash that is nevertheless on one-side of the body may be caused by:

Hemorrhagic Rash: Some of the infectious causes of a Hemorrhagic Rash:

Purpura Causes: Non-Infectious causes of purpura (petechiae, ecchymoses, hematoma, hemorrhagic rash):

Purple Striae: Causes of Purple Streak-like Marks (Purple Striae):

Causes of Skin Redness: A red skin rash, without any obvious skin changes to its texture, could be caused by:

Read more about: skin redness.

Other Infections. A localized infection can cause a skin rash or a rash-like appearance. Less commonly, a systemic infection can cause rash, and is often very serious in this case.

Chronic Rash Conditions: various chronic skin diseases can result in regular rashes, or reoccurring rashes:

Serious Disease Causes: What if it’s not just a skin condition, but a symptom of something more serious. Some of the major chronic diseases where a rash is one of the early symptoms include:

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.