8 Skin Warning Signs to Worry About in a Rash

Medically Reviewed on 3/3/2022
Most of the rashes are harmless and may not indicate anything serious.
Most of the rashes are harmless and may not indicate anything serious.

Most of the rashes are harmless and may not indicate anything serious. However, if there are these accompanying symptoms along with the skin rash, it may signify something serious.

The eight skin warning signs that need medical attention include:

  1. Widespread rashes all over the body indicate an infection or allergic reaction.
  2. Painful rashes with fever may be a sign of herpes infection. This may need evaluation by a doctor. Other rashes with fever include measles, mononucleosis, and scarlet fever.
  3. Sudden onset and rapid spreading of rash (hives) all over the body may indicate anaphylaxis. Anaphylaxis is a severe allergic reaction, which may be fatal if untreated.
  4. A blistering rash may be a sign of pemphigus vulgaris (an autoimmune condition) or a severe drug reaction. In both cases, evaluation by a doctor is a must.
  5. A sudden spread of purplish rash over the body may be a sign of infection by deadly germs or inflammation of blood vessels (vasculitis).
  6. A rash that looks like large red or purple spots under the skin may be due to the failure of the blood clotting mechanism. Such a rash is called a purpuric rash.
  7. If there is a skin discoloration or changes in the skin along with the rashes, it can indicate something serious. Yellowing of the skin indicates liver disease or darkening of the skin could signify diabetes.
  8. Bruising or swelling around the rash needs medical attention. Such a rash may be a sign of poisonous insect biting. It may cut off the blood flow of the affected area.

What are other life-threatening disorders that have skin rash as a sign?

Life-threatening disorders that have a skin rash as a major sign include:

Meningococcemia: This is caused by Neisseria meningitides and is an infectious disease. A rash is preceded by headache, nausea, vomiting, muscle pain, and joint pain.

Rocky mountain spotted fever: This is caused by Rickettsia, which is transmitted to humans by the bite of a tick. Patients initially report fevers, chills, headache, cough, muscle aches, and malaise.

Necrotizing fasciitis: It is a bacterial infection that mainly affects the legs and penetrates the deeper tissues. It is most commonly caused by group A beta-hemolytic streptococci. Fevers and chills may precede skin rashes.

Pemphigus Vulgaris (PV): PV is an autoimmune disorder in which the body’s natural system attacks its cells.

Toxic epidermal necrolysis (TEN), also known as Stevens-Johnson syndrome (SJS) or erythema multiforme major (EM): This is the severe form of an allergic reaction to antibiotics, anti-seizure medications, viral infections, and anti-HIV medications.

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome: Certain anticonvulsant medications may cause the most severe form of skin eruption that starts 2 to 6 weeks after taking the medications. Other medicines that may induce DRESS syndrome include:

Toxic shock syndrome (TSS): Certain strains of Staphylococcus bacteria cause TSS. These bacteria release toxins into the bloodstream culminating in organ damage. Other infections that may lead to TSS include:


Eczema Browse our medical image collection of allergic skin disorders such as psoriasis and dermatitis and more caused by allergies See Images

How can you tell if a rash is serious?

Shingles (Herpes Zoster)
Shingles, also known as herpes zoster, is a skin disease caused by the return of a chickenpox infection from latently infected nerve cells in the spinal cord or brain.

An itchy area of skin that’s caused by infection, allergy, or injury is known as a rash. Usually, a rash on the skin looks red and is accompanied by irritation. It may or may not be associated with pain and swelling. Rashes usually indicate an underlying medical problem in the body.

A rash can become serious if immediate medical assistance is not provided when a patient has the below symptoms:

What are the most common skin rashes caused by an infection?

Bacterial, fungal, and viral infections typically present with a skin rash as a symptom. Below are a few common skin rashes caused by infection:

Herpes zoster infection or shingles

  • It is a skin and nerve disorder caused by the varicella-zoster virus.
  • Usually seen in patients with a compromised immune system. 
  • Symptoms include abnormal redness on the skin (looks like a sunburn) with tiny multiple fluid-filled sacs (vesicles) and enlargement of the lymph nodes (where a body fluid called lymph is filtered) usually on the neck. 
  • Treatment options include vaccine and antiviral agents. 

Herpes simplex infection (HSV): 

  • It is caused by a DNA virus called herpes simplex virus. 
  • It is a sexually transmitted disease
  • Transmission occurs due to the body fluids of an infected person contacting the open skin of another person.
  • Symptoms include abnormal redness on skin (like a sunburn) with tiny multiple sacs of fluids (vesicles) on the mouth, genitals, anal region, and buttocks. 
  • There is no cure for this infection; however, infection is self-resolving. Usually, antiviral drugs are recommended by doctors to shorten the course of this disease.

Tinea corporis (ringworm):

  • It is a superficial fungal skin infection affecting moist and warm areas of the skin.
  • If it affects the feet, it is called tinea pedis; on the body, it is called tinea corporis and on the scalp or head, it is called tinea capitis.
  • Transmission occurs due to skin contact, contaminated items, or infected animals.
  • Symptoms include circular, red scaly swelling patches on the skin with pus (vesicles or bullae) or a burning sensation.
  • Treatment options include antifungal drugs. 


  • It is caused by the varicella-zoster virus.
  • This infection is highly contagious via air droplets from a contagious person and direct contact with the virus particles.
  • Usually affects children younger than 10 years old, the infection starts after 10 to 21 days of contact. 
  • Symptoms include skin rash with severe and many pus-filled sacs on the body with a low-grade fever.
  • This infection usually resolves within five to 10 days. Treatment options include only supportive therapy (keep the patient clean and healthy). Initially, it starts on the face and then develops on other sites of the body.
  • If it affects individuals with a compromised immune system, doctors usually prescribe antiviral drugs. 

Hand, foot, and mouth disease (HFMD):

  • It is caused by a highly contagious virus called coxsackievirus A16.
  • Symptoms include abnormal redness on the skin (looks like sunburn) with 2-3 mm multiple sacs of fluid (vesicles) on mouth, feet, and palms. Patients have a fever, sore throat, mouth ulcers, and loss of appetite.
  • It usually affects infants and children and is transmitted through nose and mouth secretions or fecal matter. 
  • Treatment includes supportive care with fever-reducing drugs and sometimes anesthesia for relieving the symptoms. Typically resolves within 7 days. 

Erythema infectiosum (also called the fifth disease):

  • It is a common childhood infection caused by human parvovirus B19.
  • Transmission occurs through air droplets, blood, or blood transfusion.
  • Symptoms include fever, running nose, and headache. It has three stages:
    • Stage 1: Bright abnormal redness seen on cheeks giving slapped cheek appearance.
    • Stage 2: Abnormal bright redness with vesicles extends to hands and legs.
    • Stage 3: Abnormal redness fades away, leaving a lace-like pattern on infected areas.
  • Infection resolves within seven days without treatment in children.

Pityriasis Rosea:

  • Symptoms include a large, scaly, pink area of skin, followed by additional skin spots that are itchy and red with swelling. It usually affects the back, neck, chest, abdomen, upper arms, and legs, but the rash may differ from person to person. 
  • Treatment may not be necessary, as it heals within 12 weeks with sun exposure or ultraviolet light.


  • It is a bacterial infection usually caused by Staphylococcus aureus and Streptococcus pyrogens.
  • Symptoms include pain, swelling, abnormal redness, and warmth in the infected area. 
  • Treatment includes oral or intravenous antibacterial drugs. 
Medically Reviewed on 3/3/2022