isoniazide allergy

**Isoniazid

Common Signs and Symptoms of Isoniazid Allergy

If you are allergic to isoniazid, you may experience a range of symptoms, including:

• Severe Allergic Reaction: This can manifest as hives, difficulty breathing, or swelling in the face or throat [1].
• Skin Rash: A skin rash is another common symptom of an isoniazid allergy [4][7].
• Fever: Fever that doesn't go away, new or worsening lymph nodes, and other flu-like symptoms can also be indicative of an allergic reaction to isoniazid [1][6].
• Muscle Aches: Muscle aches and severe weakness are also possible symptoms of an isoniazid allergy [7].
• Numbness or Tingling: Numbness or tingling in the hands and feet can occur due to an allergic reaction to isoniazid [4].

Other Possible Symptoms

In addition to these common symptoms, other possible signs of an isoniazid allergy include:

• Chest pain
• Coughing or spitting up blood
• Difficulty breathing
• Sore throat
• Muscle aches

If you experience any of these symptoms after taking isoniazid, seek medical attention immediately.

References: [1] Context result 1: "fever that doesn't go away, new or worsening lymph..." [2] Context result 2: "signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat)" [3] Context result 4: "eye pain · changes in vision · numbness or tingling in the hands and feet · rash" [4] Context result 7: "skin rash, fever, swollen glands, flu-like symptoms, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes." [5] Context result 8: "chest pain, cough, coughing or spitting up blood, difficulty in breathing, sore throat, muscle aches"

Diagnostic Tests for Isoniazide Allergy

Isoniazid, also known as isonicotinic acid hydrazide (INH), is a medication used to treat tuberculosis (TB). However, some individuals may be allergic to this medication. If you suspect an allergy to isoniazid, several diagnostic tests can help confirm the diagnosis.

1. Skin Tests

Skin tests are commonly used to diagnose allergies, including those caused by isoniazid. There are two types of skin tests:

• Prick test: This involves placing a small amount of the allergen (isoniazid) on the skin and pricking it with a needle. If you're allergic, a raised red bump will appear within 15-20 minutes.
• Intradermal test: This is similar to the prick test but involves injecting a small amount of the allergen into the skin.

According to [3], in one patient who underwent diagnostic testing, the prick test was positive for isoniazid. However, it's essential to note that these tests are not 100% accurate and may produce false-positive or false-negative results.

2. Oral Provocation Test

The oral provocation test (OPT) is considered the gold standard for diagnosing drug allergies, including those caused by isoniazid [9]. This test involves administering a small dose of the suspected allergen orally and monitoring for any adverse reactions. If you experience symptoms such as hives, itching, or difficulty breathing after taking isoniazid, it may indicate an allergy.

3. Specific Plasma Cell Test

The specific plasma cell test has high specificity in diagnosing hypersensitivity caused by isoniazid [2]. This test measures the levels of specific antibodies produced in response to the allergen.

4. Medical History and Physical Examination

A thorough medical history and physical examination are essential in diagnosing an allergy to isoniazid. Your doctor will ask questions about your symptoms, medical history, and any previous reactions to medications [7].

In conclusion, several diagnostic tests can help confirm an allergy to isoniazid, including skin tests (prick and intradermal), oral provocation test, specific plasma cell test, and a thorough medical history and physical examination.

References:

[1] by HJ Shin · 2021 · Cited by 17 [2] by Y Wu · Cited by 4 [3] by ZY Katran · 2022 · Cited by 7 [9] by A Baççıoglu · 2021 [7] May 8, 2024

Treatment Options for Isoniazid Allergy

If you have an allergic reaction to isoniazid, a common medication used to treat tuberculosis (TB), your doctor may need to change your treatment regimen. Here are some possible alternatives:

• Second-line anti-tuberculosis treatment: In cases of severe allergy or intolerance, patients may be switched to second-line medications such as streptomycin or quinolones [5].
• Desensitization protocols: Some patients may undergo desensitization protocols to gradually build up tolerance to isoniazid. This involves administering the medication in small doses over several days [6][7].

Medications Used During Desensitization

During desensitization, medications such as isoniazid and ethambutol are administered using 6-8 step protocols on consecutive days (Table 1) [6].

Precautions and Side Effects

To prevent certain side effects, your doctor may recommend taking vitamin B6 (pyridoxine) while on isoniazid treatment [9]. Additionally, antacids can be used to help with stomach upset; however, do not take aluminum-containing antacids within 1 hour of taking isoniazid [8].

Interactions and Contraindications

It's essential to note that certain medications may interact with isoniazid or contraindicate its use. For example, the metabolism of Albendazole can be decreased when combined with Isoniazid [10].

Differential Diagnoses of Isoniazid Allergy

Isoniazid (INH) allergy can be challenging to diagnose, and several differential diagnoses need to be considered. Here are some possible differential diagnoses:

• Jaundice: Hemolytic jaundice is a possible differential diagnosis for INH toxicity [1]. Jaundice typically precedes liver failure by only a few days, with symptoms such as fatigue, anorexia, nausea, myalgia, and arthralgia preceding it [2].
• Peripheral Neuropathy: This is another differential diagnosis for chronic INH toxicity. It can manifest as numbness, tingling, or weakness in the extremities.
• Autoimmune Disease: Several autoimmune diseases, such as lupus or rheumatoid arthritis, can present with symptoms similar to those of an allergic reaction to INH [3].
• Neoplasia: Cancer can also be a differential diagnosis for symptoms similar to those of an allergic reaction to INH.
• Active Infection: An active infection, such as tuberculosis itself, can sometimes mimic the symptoms of an allergic reaction to INH.

Other Possible Differential Diagnoses

• Multiple Drug Allergy (MDA): This is a condition characterized by hypersensitivity to 2 or more chemically unrelated drugs. MDA can be a differential diagnosis for symptoms similar to those of an allergic reaction to INH [4].
• Drug-Induced Hypersensitivity Syndrome (DRESS): DRESS is a severe cutaneous and systemic adverse drug reaction that can occur in response to certain medications, including antituberculosis drugs like INH. It can manifest as fever, rash, lymphadenopathy, and organ involvement [5].

References

[1