What allergies cause petechiae

China and Japan own the highest rates of consumption of shiitake mushrooms and the highest prevalence of shiitake dermatitis. It affects about 2% of people that consume the mushrooms raw or only lightly cooked. It has been reported in people of every ages, who are more often male than female.

More cases of shiitake dermatitis are being diagnosed in other countries where the use of shiitake mushrooms is increasing.


What is shiitake flagellate dermatitis?

Shiitake dermatitis is a distinctive rash that can happen following the ingestion of raw or undercooked shiitake mushrooms (Lentinula edodes).

It is characterised by pruritic, erythematous, linear streaks that resemble whiplash marks, hence the name flagellate.

Shiitake dermatitis is also known as flagellate erythema and toxicodermia.


What causes petechiae?

Petechiae happen when little blood vessels under the skin break.

The most common cause of petechiae is physical trauma. Petechiae may also spontaneously appear in aging skin.

Petechiae may be a sign of serious blood disorders in which blood fails to clot. The inability to form blood clots and the resulting petechiae may also happen because of certain medications.

Serious or life-threatening causes of petechiae

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

  1. Serious infections such as enterovirus infection or meningococcal infection

  2. Thrombocytopenia (low blood platelet count; platelets assist form clots to stop blood loss)

  3. Blood clotting factor defect

  4. Idiopathic thrombocytopenic purpura (thrombocytopenia with no known cause)

  5. Disseminated intravascular coagulation (a syndrome that results in depletion of blood clotting factors)

  6. Exposure to toxic substances or poisoning (rodenticide)

  7. Von Willebrand’s disease (hereditary bleeding disorder)

Drug-related causes of petechiae

Petechiae can also be caused by reactions to certain medications.

Examples include:

  1. Heparins such as low molecular weight heparin

  2. Phenytoin (Di-Phen, Dilantin)

  3. Acetaminophen (Tylenol) and naproxen (Aleve, Naprosyn)

  4. Cimetidine (Tagamet)

  5. Carbamazepine (Carbatrol, Tegretol)

  6. Chlorothiazide (Chlotride, Diuril)

  7. Rifampin (Rifadin, Rimactane) and linezolid (Zyvox)

Traumatic causes of petechiae

Petechiae may be caused by physical trauma including:

  1. Heavy lifting with extreme straining

  2. Violent coughing

  3. Choking

  4. Excessive crying

  5. Vomiting including multiple episodes

Questions for diagnosing the cause of petechiae

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

  1. Have you had any recent physical trauma?

  2. When did you first notice the red dots or purple bruising?

  3. What medications are you taking?


What causes shiitake flagellate dermatitis?

Shiitake flagellate dermatitis is a toxic reaction to lentinan, found in unused, powdered, or lightly cooked shiitake mushrooms.

Lentinan is a thermolabile polysaccharide that activates interleukin 1 secretion, leading to vasodilation, haemorrhage and rash.

This hypothesis is supported by the observation that shiitake dermatitis is not seen with the ingestion of thoroughly cooked at a temperature > C.

Flagellate dermatitis does not result from cutaneous contact with the mushrooms.


What are petechiae?

Petechiae are little red or purple dots of blood that appear on the skin or in the mucus membranes.

The mouth is one mucus membrane where petechiae may happen. Petechiae happen when superficial blood vessels under the skin break. Petechiae may glance love a rash.

The most common cause of petechiae is through physical trauma, such as a violent coughing fit, prolonged vomiting, or excessive crying.

What allergies cause petechiae

This helpful of trauma can result in facial petechiae, particularly around the eyes. Petechiae may also appear in aging skin. These forms of petechiae are generally harmless and vanish within a few days.

Petechiae may also be a sign of a serious blood disorder called thrombocytopenia. In this disease, blood platelet levels are decreased and blood clotting is impaired. Petechiae may also be a sign of another platelet-related disorder called idiopathic thrombocytopenic purpura, which is thrombocytopenia with no known cause.

The impairment in ability to form blood clots and the resulting petechiae may also happen because of certain medications you may be taking.

These drugs include antiplatelet medications, anticoagulants, aspirin, and steroids.

Sudden and unexplained bleeding under the skin may be a medical emergency. Seek immediate medical care (call ) if you, or someone you are with, own any symptoms including high fever (higher than degrees Fahrenheit), confusion or loss of consciousness for even a brief moment, or severe headache.

Seek immediate medical care if you are taking these types of medications and experience petechiae.


What are the potential complications of petechiae?

Petechiae originating from physical trauma should resolve in a few days.

Petechiae related to an underlying blood clotting disorder or other serious condition can be serious, and failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is significant 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:

  1. Severe or uncontrolled bleeding

  2. Intracranial hemorrhage (bleeding inside the skull or brain)

  3. Chronic poisoning

  4. Spread of infection

What should you tell the family about the patients prognosis?

  1. Consider if the patient is well enough to provide medical and non-medical information at admission or requires immediate cardio-respiratory support.

  2. If the infectious agent is transmitted by droplet or airborne spread (either viral or bacterial disease), the patient must be isolated.

    Start appropriate universal precautions. Health care workers should exercise caution and use standard precautions. Gloves should always be worn during examination of the skin, and avoid intimate contact with secretions. In the event of a potential exposure to a pathogen, start post-exposure prophylaxis and determine if work restrictions are needed.

  3. Prognosis of fever and rash is sure by the cause and by the nature of the underlying disease(s). Childhood viral exanthems are generally self-limited and uneventful.

  4. The underlying cause determines its potential for recurrence.

    Some diseases own protracted courses and may cause serious complications (e.g., Kawasaki disease, lupus).

  5. Patients’ life-threatening conditions, such as meningococcemia, toxic shock syndrome, toxic epidermal necrolysis, and ebola disease own high mortality. Immunocompromised patients own the poorest prognosis.

  6. Consider an exotic disease acquired as a result of travel or the intentional release of a potentially bioterrorism agent.

How can fever and rash be prevented?

Prevention of diseases causing fever and rash is hard. Cough etiquette, contact precautions, and hand hygiene are simple and cost-effective measures in reducing the spread of infectious agents causing fever and rash.

Avoiding unnecessary drug prescriptions prevents drug-related adverse events.

For measles, mumps, rubella (MMR) prevention can be achieved by vaccination (two doses in childhood). In adolescents and adults, if none confirmatory immunization documentation exists, they need to get two doses of MMR, at least 4-week apart. MMR is contraindicated in pregnancy, HIV with CD4 lymphocyte < cells/mm3, or immune compromised patients.

Prevention of varicella and meningococcemia can also be achieved by vaccination. Both vaccines own been accepted in most national immunization programs. There are variations across the globe depending on the epidemiology of the disease (e.g., meningococcal disease), health budget, and authority decisions (e.g., varicella vaccine is not on the immunization program of France or the United Kingdom).

For meningococcal disease, chemoprophylaxis can also be useful.

Among household contacts, the incidence of transmission of meningococcus is approximately 5%; therefore, it is recommended that household contacts of bacteriologically confirmed cases get rifampin (adults: mg bid for a entire of 4 doses; children older than 1 month: 10 mg/kg; children younger than 1 month: 5 mg/kg). These contacts should be advised to watch for fever, rash, sore throat, or any symptoms of meningitis. Intimate, non-household contacts who own had mucosal exposure to the patients oral secretions should also get prophylaxis.

Health-care workers are not at an increased risk for the disease and do not require prophylaxis unless they own had direct mucosal contact with patient secretions (i.e., mouth-to-mouth resuscitation, endotracheal intubation, or nasotracheal suctioning).

What allergies cause petechiae

Ciprofloxacin ( mg by mouth; adults only) or ceftriaxone ( mg IM for adults or mg IM for children) are single dose alternatives.

With the increasing vector borne diseases (e.g., Zika, chinkungunya, dengue, yellow fever) efforts to prevent mosquito bites are cornerstone. Some of the recommended measures in persons living or traveling to endemic areas are:

  1. Bleeding into the skin. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  2. Idiopathic thrombocytopenic purpura (ITP).

    PubMed Health, a service of the NLM from the NIH.

  3. If possible, hold indoors at sunset.

  4. Use Environmental Protection Agency (EPA)-registered insect repellents with one of the following athletic ingredients: DEET (≥20%), picardin, IR, oil of lemon eucalyptus, or para-menthane-diol.

  5. Long-sleeved shirts and pants.

  6. Cover water storage containers so that mosquitos cannot get inside to lay eggs.

  7. Sleep under a mosquito bed net if you are overseas or exterior and are not capable to protect yourself from mosquito bites.

  8. Discard or empty regularly any items that hold water love tires, buckets, pools, birdbaths, flowerpot saucers, or trash containers.

  9. What is immune thrombocytopenia?

    National Heart, Lung, and Blood Institute Diseases and Conditions Index.

  10. Kahan S, Miller R, Smith EG (Eds.). In A Sheet Signs & Symptoms, 2d ed. Philadelphia: Lippincott, Williams & Williams,

For men who live in or own traveled to an area with Zika, and own a pregnant partner they either own to use condoms correctly from start to finish, every time they own vaginal, anal, and oral sex, or do not own sex during pregnancy.

Women who had Zika virus disease should wait at least 8 weeks after exposure to attempt conception and men with Zika virus disease should wait at least 6 months after symptom onset to attempt conception.

Women and men with possible exposure to Zika virus but without clinical illness consistent with Zika virus disease should wait at least 8 weeks after exposure to attempt conception.

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Medical References

  • When patients own a life-threatening condition, empiric therapy is of high priority and should be started even before a diagnostic culture or biopsy can be taken. A focused history and clinical features are most useful; reducing the possibilities to a extremely limited differential diagnostic list helps in the selection of empiric treatment.

    Necrotizing fasciitis, meningococcemia and Rocky spotted mountain fever are conditions in which empirical treatment should be started early during patients admission and not be delayed waiting for laboratory results. In some conditions (e.g., necrotizing fasciitis), emergency surgical debridement is also performed.

  • The utility of empiric therapy is limited to a few causes, because numerous agents causing fever and rash are of viral etiology.

  • Bleeding into the skin.

    Medline Plus, a service of the National Library of Medicine National Institutes of Health.

  • Kahan S, Miller R, Smith EG (Eds.). In A Sheet Signs & Symptoms, 2d ed. Philadelphia: Lippincott, Williams & Williams,
  • What is immune thrombocytopenia? National Heart, Lung, and Blood Institute Diseases and Conditions Index.
  • Idiopathic thrombocytopenic purpura (ITP). PubMed Health, a service of the NLM from the NIH.
  • There are other bacterial infections in which antimicrobial treatment should be initiated as soon as the initial diagnostic work-up has been completed (i.e., leptospirosis, scarlet fever, staphylococcal infections, endocarditis, Lyme disease).

    For initial drug treatment, please refer to published guidelines and recommendations.

Imaging tests are not cornerstone in the diagnostic work-up of an uneventful episode of fever and rash.

Imaging studies are generally ordered in life-threatening conditions, patients with serious underlying diseases (i.e., immunosuppression), and individuals in whom a complication is suspected.

A patient centered evaluation should dictate the sequence and type of study. (See Table VIII)

Table VIII.
Imaging Studies Clinical Setting Condition
Head CT and/or Brain MRI Fever and rash + abnormal neurological examination (aseptic meningitis, meningitis) Meningococcemia, rickettsial infection.

Severe forms of varicella and herpes. Complicated measles

CT Scan (region depends on extent of affection) Systemic toxicity + rapidly progressing soft tissue necrosis (presence of free air in soft tissues) Necrotizing fasciitis
Liver and Spleen Ultrasound Severe hepatosplenomegaly Infectious mononucleosis (protracted course).

What allergies cause petechiae

Any disease with serious hepatic and/or splenic involvement

Transesophageal Echocardiography Heart murmur + continuous bacteremia and/or peripheral manifestations of endocarditis Subacute bacterial endocarditis

What consult service or services would be helpful for making the diagnosis and assisting with treatment?

If you decide the patient has fever and rash, what therapies should you initiate immediately?

The disorders responsible for fever and rash are numerous, and their manifestations protean; therefore, multiple specialists are frequently involved on the diagnostic approach.

Family Physicians, Dermatologists, Emergency services, Pediatricians, Internal Medicine, and Infectious Diseases Physicians are frequently consulted.

Depending on the clinical condition and severity of the disease, Rheumatologists, Intensive Care doctors and Oncologists may also be involved during the diagnostic work-up and treatment. In some life-threatening disorders, such as necrotizing fasciitis, surgeons must be consulted.

Empiric therapy

  1. When patients own a life-threatening condition, empiric therapy is of high priority and should be started even before a diagnostic culture or biopsy can be taken.

    What allergies cause petechiae

    A focused history and clinical features are most useful; reducing the possibilities to a extremely limited differential diagnostic list helps in the selection of empiric treatment. Necrotizing fasciitis, meningococcemia and Rocky spotted mountain fever are conditions in which empirical treatment should be started early during patients admission and not be delayed waiting for laboratory results. In some conditions (e.g., necrotizing fasciitis), emergency surgical debridement is also performed.

  2. The utility of empiric therapy is limited to a few causes, because numerous agents causing fever and rash are of viral etiology.

  3. There are other bacterial infections in which antimicrobial treatment should be initiated as soon as the initial diagnostic work-up has been completed (i.e., leptospirosis, scarlet fever, staphylococcal infections, endocarditis, Lyme disease).

    For initial drug treatment, please refer to published guidelines and recommendations.

WHATS THE EVIDENCE for specific management and treatment recommendations?

Meurer, WJ, Lavoie, FW.. Central nervous system infections. Rosen’s emergency medicine: concepts and clinical practice.

Gilbert, DN, Chambers, HF, Eliopoulos, GM, Saag, MS. The Sanford Guide to Antimicrobial Therapy.

What allergies cause petechiae

CDC 24/7: Saving Lives. Protecting People. Zika Virus.

Copyright , Decision Support in Medicine, LLC. Every rights reserved.

No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.

Powered By Decision Support in Medicine.

Author: Emma Trowbridge, Registrar, Department of Dermatology, Christchurch Hospital, Christchurch, New Zealand, January Updated byLauren Thomas, 3rd Year Postgraduate Medical Student, Flinders University, Northern Territory, Australia;Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, September


Imaging tests are not cornerstone in the diagnostic work-up of an uneventful episode of fever and rash.

Imaging studies are generally ordered in life-threatening conditions, patients with serious underlying diseases (i.e., immunosuppression), and individuals in whom a complication is suspected.

A patient centered evaluation should dictate the sequence and type of study.

(See Table VIII)

Table VIII.
Imaging Studies Clinical Setting Condition
Head CT and/or Brain MRI Fever and rash + abnormal neurological examination (aseptic meningitis, meningitis) Meningococcemia, rickettsial infection. Severe forms of varicella and herpes. Complicated measles
CT Scan (region depends on extent of affection) Systemic toxicity + rapidly progressing soft tissue necrosis (presence of free air in soft tissues) Necrotizing fasciitis
Liver and Spleen Ultrasound Severe hepatosplenomegaly Infectious mononucleosis (protracted course).

Any disease with serious hepatic and/or splenic involvement

Transesophageal Echocardiography Heart murmur + continuous bacteremia and/or peripheral manifestations of endocarditis Subacute bacterial endocarditis

What consult service or services would be helpful for making the diagnosis and assisting with treatment?

If you decide the patient has fever and rash, what therapies should you initiate immediately?

The disorders responsible for fever and rash are numerous, and their manifestations protean; therefore, multiple specialists are frequently involved on the diagnostic approach.

Family Physicians, Dermatologists, Emergency services, Pediatricians, Internal Medicine, and Infectious Diseases Physicians are frequently consulted.

Depending on the clinical condition and severity of the disease, Rheumatologists, Intensive Care doctors and Oncologists may also be involved during the diagnostic work-up and treatment. In some life-threatening disorders, such as necrotizing fasciitis, surgeons must be consulted.

Empiric therapy

  1. When patients own a life-threatening condition, empiric therapy is of high priority and should be started even before a diagnostic culture or biopsy can be taken.

    A focused history and clinical features are most useful; reducing the possibilities to a extremely limited differential diagnostic list helps in the selection of empiric treatment. Necrotizing fasciitis, meningococcemia and Rocky spotted mountain fever are conditions in which empirical treatment should be started early during patients admission and not be delayed waiting for laboratory results. In some conditions (e.g., necrotizing fasciitis), emergency surgical debridement is also performed.

  2. The utility of empiric therapy is limited to a few causes, because numerous agents causing fever and rash are of viral etiology.

  3. There are other bacterial infections in which antimicrobial treatment should be initiated as soon as the initial diagnostic work-up has been completed (i.e., leptospirosis, scarlet fever, staphylococcal infections, endocarditis, Lyme disease).

    For initial drug treatment, please refer to published guidelines and recommendations.

WHATS THE EVIDENCE for specific management and treatment recommendations?

Meurer, WJ, Lavoie, FW.. Central nervous system infections. Rosen’s emergency medicine: concepts and clinical practice.

Gilbert, DN, Chambers, HF, Eliopoulos, GM, Saag, MS. The Sanford Guide to Antimicrobial Therapy.

CDC 24/7: Saving Lives. Protecting People. Zika Virus.

Copyright , Decision Support in Medicine, LLC.

What allergies cause petechiae

Every rights reserved.

No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.

Powered By Decision Support in Medicine.

Author: Emma Trowbridge, Registrar, Department of Dermatology, Christchurch Hospital, Christchurch, New Zealand, January Updated byLauren Thomas, 3rd Year Postgraduate Medical Student, Flinders University, Northern Territory, Australia;Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, September



What other symptoms might happen with petechiae?

Petechiae may accompany other symptoms, which vary depending on the underlying disease, disorder, or condition.

Symptoms that may happen along with petechiae

Petechiae may accompany other symptoms including:

  1. Joint hemorrhage (hemarthrosis)
  2. Heavy bleeding during menstrual periods (menorrhagia)
  3. Collection of clotted blood under the skin (hematoma)
  4. Excessive bleeding from the gums
  5. Easy bleeding or bruising
  6. Unexplained nosebleeds

Serious symptoms that might indicate a life-threatening condition

In some cases, petechiae may be a symptom of a life-threatening condition that should be immediately evaluated in an emergency setting.

Seek immediate medical care (call ) if you, or someone you are with, own any of these life-threatening symptoms including:

  1. Severe bleeding
  2. High fever (higher than degrees Fahrenheit)
  3. Confusion or loss of consciousness for even a brief moment
  4. Severe headache


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