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Diagnosis and Treatment


D.R.E.S.S. syndrome is a challenging diagnosis as it is an uncommon condition that occurs progressively, involves many clinical symptoms including fever, rash, facial swelling, enlarged lymph nodes and organ injury, and requires a number of diagnostic tests. Because DRESS can affect multiple organs and present with a number of lab abnormalities, physicians must rule out other diseases and types of drug reactions and have a high level of suspicion for DRESS.

Common Diagnostic Tests may include:

  • Blood

  • Bone marrow

  • Organs/organ biopsies

  • Skin biopsy

  • Urine

Additional Tests that may be needed:

  • CT scan

  • Echocardiograph (EC)

  • Echocardiogram (ECC)

  • MRI

  • Ultrasound

  • X-ray

Many DRESS patients will have an abnormal level of blood cells called eosinophils show up in their blood tests. This condition is called eosinophilia. Eosinophils are associated with allergic diseases and, in abundance, can wreak havoc on organs. However, while it’s in the name of this condition, eosinophils are not always evident in the blood. Often, another type of white blood cell, atypical lymphocytes, may show up in blood labs — in lieu of or in addition to eosinophilia. For this reason, some prefer the acronym DReSS with a lower case "e."

While there is not a 100% definitive test for diagnosing DRESS, international experts have developed tools that have become best practice to help physicians confirm or exclude the diagnosis.

Evaluation of signs, symptoms, medical history and laboratory findings are all part of the work-up. If DRESS is suspected, referring to the international diagnostic scoring charts can help aid your physician in making a proper diagnosis. 


The Registry of Severe Cutaneous Adverse Reactions (RegiSCAR), the Japanese Consensus Group (J-SCAR) and Boquet et al# are all scoring systems which use a set of defined criteria to make the determination of DRESS.

By comparison, the J-SCAR includes the detection of HHV-6 viral reactivation. If present, the Japanese refer to the condition as DIHS (Drug-induced hypersensitivity syndrome).

It’s important to note that while these tools are helpful, some of the scoring criteria are for symptoms that may occur later in the disease or may be transient and not detectable at the time of diagnostic testing. The golden rule should be to assume DRESS in a patient who’s taken medication and presents with delayed symptoms of: fever, rash, facial edema/swelling, and enlarged lymph nodes.














*Test that may be done initially to help with diagnosis and to evaluate patient's symptoms during course of illness.

Complete blood count w/differential and peripheral blood smear (CBC)

  • Eosinophilia (>700micorL),

  • Lymphocytosis (absolute lymphocyte count >4500/microL), and/or

  • Atypical lymphocytes on peripheral smear


Liver function tests (LFT)

  • Elevated enzymes 1.5 to 2 times the normal value

  • ALT (serum alanine aminotransferase)

  • AST (aspartate transaminase)

  • ALP (alkaline phosphate)

  • Bilirubin

  • Gamma-glutamyl transferase


Kidney: Serum creatinine and urinalysis

  • Moderate elevation in creatinine level

  • Low grade proteinuria

  • Indications of kidney involvement: abnormal urinary sediment w/ occasional eosinophils

Heart (Cardiac) Function:

  • Troponin T


  • TSH

  • Free T4


  • CK

Serology for viral hepatitis

  • Hepatitis A IgM antibody

  • Hepatitis B surface antigen

  • Hepatitis B core IgM antibody

  • Hepatitis C viral RNA


Tests for herpes viral infection

  • qPCR: HHV-6, HHV-7, EBV and CMV

Active or reactivated virus: human herpes virus-6 (HHV-6), human herpes virus-7 (HHV-7), Epstein-Barr virus (EBV), and cytomegalovirus (CMV) using quantitative polymerase chain reaction (qPCR) on serum or plasma. Test upon admission and again in two to three weeks as the viral load detection in blood has a latency of this time period.

HHV-6 is known to preferentially reactivate in DRESS as opposed to other severe drug reactions and could be an important clue in diagnosis. Patients with viral reactivation tend to have a more severe and prolonged course of illness. Detailed viral testing information can be found here:

Additional Lab Test

  • Electrolytes in blood and urine

  • Serum creatine phosphokinase and troponin

  • Serum lactic dehydrogenase, ferritin, and triglycerides

  • Serum calcium and procalcitonin

  • Serum glucose

  • Prothrombin time and activated partial thromboplastin time

  • Serum lipase

  • Serum protein electrophoresis

  • Antinuclear antibodies, blood cultures (to rule out other diagnoses)


Skin Biopsy
Findings that may support diagnosis

  • Mild spongiosis

  • Infiltrate of atypical lymphocytes

  • Increased eosinophils

  • Dermal edema


Genetic Testing

In cases where a drug and genetic association is known, such as with the antibiotic, Vancomycin, genetic testing for the HLA markers specific to that drug may help aid in diagnosis. These genetic test are generally simple and cost-effective but are underutilized in clinical practice. Currently, we know of only a handful of what the genetic markers are for certain drugs that can predispose some to get DRESS. See "Drugs Associated with DRESS" for the currently known drug/gene associations.

*References: (DRESS syndrome: Descamps/Ranger-Rogez), (Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part II diagnosis and management: B Wei et al.)


The first order of action with DRESS is to identify and stop the offending medication.


Treatments of DRESS Syndrome will vary by case, taking into consideration severity, other existing medical conditions and the presence of viral reactivation. 

The most commonly accepted core treatment for DRESS is systemic corticosteroids and oral prednisone. They may be indicated when organs are affected and could decrease the chance of symptom flare-ups and also autoimmune complications. Systemic steroids are typically started at a high dose and weaned very slowly (6-8 weeks or longer) to reduce the chance of disease reoccurrence. Patients who have a difficult time weaning from steroids without a flare in symptoms may be treated with additional, supportive (steroid-sparing) medications. Topical steroids (creams and ointments) are also often used to reduce skin inflammation and irritation.

It's important to note that tapering steroids slowly, with a minimum of 6-12 weeks (some patients will need a longer course) can help avoid a return or worsening of symptoms.


Other treatments a patient may need include:






*Note: While no large clinical trial currently exists to support treating DRESS Syndrome, a global medical community of DRESS experts has recently (2024) proposed best practices on how to diagnose and treat patients. They based their suggestions on literature and their clinical experiences. See our booklet "Know the Facts About DRESS" for more information. You can also refer your physician to this two-part published paper on the Pathogenesis and Clinical Features and Diagnosis and Management of DRESS.

Prognosis and Long-Term Complications >

  • Antivirals (in cases with viral reactivation)    

  • Cyclosporine

  • Intravenous Immunoglobulin (IVIG)

  • Interleukin-5 axis inhibitors

  • Janus kinase inhibitors (JAK)

  • Mycophenolate mofetil (Cellcept)

  • Rituximab

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