What are the other Names for this Condition? (Also known as/Synonyms)

• IGDR (Interstitial Granulomatous Drug Reaction)
• Interstitial Granulomatous Drug Eruption

What is Interstitial Granulomatous Drug Reaction? (Definition/Background Information)

• Interstitial granulomatous dermatitis (IGD) is a form of granulomatous dermatitis, an uncommon skin condition, which presents skin rashes mostly in middle-aged women with autoimmune disorders
• Interstitial Granulomatous Drug Reaction (IGDR) is the development of interstitial granulomatous dermatitis triggered by medication use. IGDR is mostly associated with antihypertensives; and, the skin rashes are mostly observed to develop in the skin folds such as the armpits
• Stopping or discontinuing the use of such medications may decrease progression of Interstitial Granulomatous Drug Reaction and/or may result in resolution of the condition. The prognosis of IGDR on stoppage of the medication is excellent in a vast majority of cases

Who gets Interstitial Granulomatous Drug Reaction? (Age and Sex Distribution)

• Interstitial Granulomatous Drug Reaction is a rare condition and individuals of all ages may be affected
• Both males and females are known to be affected
• The condition may affect individuals of all racial and ethnic groups

What are the Risk Factors for Interstitial Granulomatous Drug Reaction? (Predisposing Factors)

The key risk factor for Interstitial Granulomatous Drug Reaction is the use of certain medications (to treat other health conditions) that lead to the skin condition as an unintended side effect or complication. The medications implicated in IGDR include:

• Antihypertensive medications such as:
  • Angiotensin-converting enzyme (ACE) inhibitors
  • Beta blockers
  • Calcium channel blockers
  • Diuretics
• Anticonvulsants
• Antidepressants
• Antihistamines
• Lipid-lowering agents such as statins
• Tumor necrosis factor (TNF) alpha blockers such as adalimumab, etanercept, infliximab, certolizumab pegol, golimumab

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Interstitial Granulomatous Drug Reaction? (Etiology)

• Interstitial Granulomatous Drug Reaction (IGDR) develops from the use of certain medications/drugs that are administered for various health conditions. It is believed that the offending drug potentially causes an abnormal cell-mediated immune response in the body 
• The onset of IGDR may be slow or rapid. Sometimes, the appearance of signs and symptoms due to the drug may not be observed immediately after starting the medication, but after a certain period of time

What are the Signs and Symptoms of Interstitial Granulomatous Drug Reaction?

The signs and symptoms of Interstitial Granulomatous Drug Reaction may vary from one individual to another. It may also be mild or severe and may be related to the type and usage of the drug. The signs and symptoms may include:

• Presence of numerous nodules and plaques; the lesions are commonly annular or ring-shaped
• These granulomatous skin lesions may range in color from buff-colored to pink to red
• The lesions are known to favor the skin folds; other body sites include the chest and back, upper arms, and thighs
• Sometimes, the lesions may present mild itching to burning sensation
• Waxing and waning of the lesions may be noted

How is Interstitial Granulomatous Drug Reaction Diagnosed?

The following tests and exams may be used in diagnosing Interstitial Granulomatous Drug Reaction:

• Evaluating the clinical history (physical exam) and a thorough family history (including current medication use)
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• KOH tests to rule out a fungal infection
• Skin tissue biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Interstitial Granulomatous Drug Reaction?

The complications of Interstitial Granulomatous Drug Reaction are not very significant, but may include the following:

• Emotional stress
• Cosmetic concerns
• Recurrence of the condition

How is Interstitial Granulomatous Drug Reaction Treated?

Discontinuation of the causative medication may result in a cure or improvement of Interstitial Granulomatous Drug Reaction.

If necessary, based on the healthcare provider’s evaluation, symptomatic treatment may be undertaken via the following measures:

• Use of topical steroid creams and ointments
• Oral and systemic steroids, if necessary
• Administration of medications such as dapsone, hydroxychloroquine, and methotrexate

How can Interstitial Granulomatous Drug Reaction be Prevented?

Current medical research has not established a method of preventing Interstitial Granulomatous Drug Reaction. However, the following measures may be considered to help lower one’s risk for the condition:

• Drugs that cause the condition may be discontinued or alternative medication prescribed; nevertheless, this has to be decided by the healthcare expert
• Avoid self-medication or bringing about any changes to one’s medication dosage without consulting the healthcare provider
• Inform your physician if you are allergic to any medication

What is the Prognosis of Interstitial Granulomatous Drug Reaction? (Outcomes/Resolutions)

The prognosis of Interstitial Granulomatous Drug Reaction is usually good in many cases, upon discontinuation of the medication and adequate treatment of the condition, as needed.

Additional and Relevant Useful Information for Interstitial Granulomatous Drug Reaction:

Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition.