Medication Summary
The goal of pharmacotherapy is to eradicate the underlying mycobacterial infection that causes papulonecrotic tuberculid.
Antitubercular agents
Class Summary
These agents are effective in the treatment of mycobacterial infections. Therapy with a 4-drug combination of rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) is recommended to avoid the development of resistance.
Isoniazid (Laniazid, Nydrazid)
Isoniazid is the best combination of effectiveness, low cost, and minor adverse effects. It is a first-line drug unless resistance or another contraindication is known. Therapeutic regimens of less than 6 months demonstrate an unacceptably high relapse rate. Coadministration of pyridoxine is recommended to minimize the risk of peripheral neuropathy secondary to isoniazid therapy. Prophylactic doses of 6-50 mg of pyridoxine daily are recommended. Twice-weekly dosing is not recommended in HIV patients with CD4 lymphocyte counts of less than 100 cells/µL.
Rifampin (Rifadin, Rimactane)
Rifampin is for use in combination with at least one other anti-TB drug. It inhibits DNA-dependent bacterial RNA polymerase but not mammalian RNA polymerase. Cross-resistance may occur. Treat for 6-9 months or until 6 months have elapsed from conversion to sputum culture negativity.
Pyrazinamide
Pyrazinamide is a pyrazine analog of nicotinamide that may be bacteriostatic or bactericidal against M tuberculosis, depending on the concentration of the drug attained at the site of infection; its mechanism of action is unknown. Administer for the initial 2 months of a 6-month or longer treatment regimen for drug-susceptible patients. Treat drug-resistant patients with individualized regimens.
Ethambutol (Myambutol)
Ethambutol diffuses into actively growing mycobacterial cells, such as tubercle bacilli. It impairs cell metabolism by inhibiting the synthesis of one or more metabolites, which, in turn, causes cell death. No cross-resistance is demonstrated. Mycobacterial resistance is frequent with previous therapy. Use ethambutol in these patients in combination with second-line drugs that have not been previously administered. Administer daily until permanent bacteriologic conversion and maximal clinical improvement is seen. Absorption is not significantly altered by food.
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Bilaterally symmetric papulonecrotic lesions on the lower extremities.
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Papulonecrotic tuberculid. Higher magnification shows better detail of the area of necrosis surrounded by a granulomatous process. Courtesy of Prof Oscar Tellechea, MD, and José Carlos Cardoso, MD.
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Papulonecrotic tuberculid. Multinucleated giant cells are noted within the granulomas. Courtesy of Prof Oscar Tellechea, MD, and José Carlos Cardoso, MD.
