Situation: The nurse at a Rural Health Unit (RHU) runs the skin clinic of the Leprosy Control Program and follows up the families of clients with leprosy and tuberculosis (TB). In the 4th month of multidrug therapy (MDT), a client's existing patches become red, swollen, and painful, and he has new pain along the ulnar nerve. What should the nurse do?

Existing lesions that become red, swollen, and painful with new nerve pain are a type 1 (reversal) reaction, an immune flare that can damage nerves quickly. MDT is continued, and the client is referred urgently for corticosteroids such as prednisolone and nerve assessment. A reaction is not treatment failure.

The client’s presentation during month 4 of multidrug therapy (MDT) — pre-existing skin patches becoming red, swollen, and painful, along with new pain along the ulnar nerve — is characteristic of a type 1 (reversal) reaction. This is an acute, immune-mediated inflammatory episode that can occur before, during, or after starting MDT and is a major cause of nerve damage and disability in leprosy ^[1]. The correct nursing action is to continue MDT and refer the client urgently for corticosteroid therapy and nerve assessment.

Why this is a reaction, not treatment failure
A type 1 reaction reflects a sudden increase in cell-mediated immunity against Mycobacterium leprae antigens, not drug resistance or failure of the MDT regimen. The inflamed skin patches and new ulnar nerve pain indicate that the immune system is now aggressively attacking residual bacilli within the skin and peripheral nerves ^[1][3]. Stopping MDT would remove the antimicrobial backbone that is reducing the bacterial antigen load, potentially worsening the inflammatory process over time. Therefore, option 1 (stop MDT) and option 4 (stop dapsone) are incorrect because the reaction is not caused by the drugs themselves.

Why urgent corticosteroids are needed
The most concerning feature here is the new pain along the ulnar nerve. Leprosy neuropathy can be acute and frequently occurs during reactional episodes ^[2]. Neuritis can cause irreversible loss of nerve function if left untreated, and the recommended treatment is corticosteroid therapy, usually oral prednisolone at an immunosuppressive dose ^[2][3]. Delaying referral until the next monthly dose (option 3) risks permanent nerve damage, weakness, and deformity. The nurse at the Rural Health Unit should recognize this as an emergency requiring same-day or urgent referral.

Clinical recognition of type 1 reaction
The key features that distinguish a type 1 reaction from simple disease progression or drug hypersensitivity are summarized below.

Feature	Type 1 (reversal) reaction	Dapsone hypersensitivity	Treatment failure
Skin changes	Existing patches become red, swollen, painful	Generalized rash, fever, lymphadenopathy	New lesions or slowly enlarging old lesions without acute inflammation
Nerve involvement	New nerve pain, tenderness, or functional loss	Not typical	Gradual, not acute
Onset	Often during first 6–12 months of MDT	Usually within first 6 weeks of dapsone	Any time, but without acute flare
MDT management	Continue MDT	Stop dapsone immediately	Evaluate adherence and resistance
Additional treatment	Urgent corticosteroids	Supportive care, stop offending drug	May require regimen change

Key point! A leprosy reaction is an immune flare, not a sign that MDT is failing. The antimicrobial therapy must continue while the inflammatory component is suppressed with corticosteroids.

Nursing role in the RHU setting
The nurse should perform a focused neurological assessment of the affected ulnar nerve distribution, checking for sensory loss, muscle weakness, or clawing of the ring and little fingers. High-resolution ultrasonography can detect dynamic inflammatory changes in peripheral nerves during MDT, but clinical examination remains the first-line screening tool in most RHU settings . The client should be referred urgently for initiation of prednisolone, with clear documentation of the reaction type, nerve involvement, and MDT adherence.

Watch out! Never wait for the next scheduled monthly visit when new nerve pain appears during MDT. Nerve damage from leprosy neuritis can become irreversible within days to weeks if corticosteroids are delayed ^[2][3].