Management of DR-TB ADR: Rash, Allergy and Anaphylaxis Reaction

Hypersensitivity reactions like rashes, allergies and anaphylactic reactions are common Adverse Drug Reactions (ADRs) to any of the second-line anti-TB drugs. 

These ADRs are often reported by patients themselves.

Milder forms of this ADR present with a localised rash that is not associated with mucus membranes. In such cases, patients can be reassured and managed symptomatically at home or at the Peripheral Health Institution (PHI).

Serious cases might present with generalized patchy lesions and should be referred to the district/ nodal DR-TB centre.

Drugs that have been identified as the cause of these reactions must be noted in the Drug-resistant TB (DR-TB) treatment card.

Suspected Agent(s): Any second-line anti-TB drug

Management Strategies

• Eliminate other potential causes of allergic skin reactions (e.g., scabies or other environmental agents).
• Mild reaction: Reassure the patient and manage symptomatically with the doctor.
• Minor dermatologic reactions: Continue anti-TB medications and:
  • Include antihistamines, hydrocortisone cream for localized rash
  • Prednisone in a low dose of 10 to 20 mg per day for several weeks, if other measures are not helpful
  • Use a moisturizing lotion for dry skin related itching (especially in diabetics)
• Serious allergic reactions: Stop all therapies pending resolution of reaction and refer the patient to a nodal DR-TB centre/ tertiary centre for further management.
• Anaphylaxis: Follow standard emergency protocols.

Points to Note

• History of previous drug allergies to be reviewed.
• Any known drug allergies are to be noted on the DR-TB treatment card.
• Flushing reaction to Pyrazinamide (Z) is usually mild and resolves with time. 
• Hot flushes, itching, palpitations can be caused by Isoniazid (H) and tyramine-containing foods (cheese, red wine). If this occurs, advise patients to avoid foods that precipitate reactions.
• Any of the drugs can cause hives (urticaria). To identify the drug, introduce drugs one at a time and in case of hives, a desensitization attempt can be made.

Once the rash resolves, reintroduce the remaining drugs, one at a time with the one most likely to cause the reaction last. The order of reintroduction will be Isoniazid (H), Pyrazinamide (Z), Ethionamide (Eto), Ethambutol (E), Fluoroquinolone (FQ). 

Consider not reintroducing, even as a challenge, any drug that is highly likely to be the cause of anaphylaxis or Stevens-Johnson syndrome and suspend any drug identified to be the cause of a serious reaction permanently.

 Resources

• Guidelines for Programmatic Management of Drug-resistant Tuberculosis in India, March 2021.
• Technical and Operational Guidelines for TB in India, 2016.

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