Step 1: Under the Suraksha Clinic STI/RTI service of NACO, ready-to-use drug kits are colour labelled. The clinician matches the patient's main complaint to a coloured pack rather than waiting for a culture report.
Step 2: Among these, the pack coloured blue corresponds to ulcerative lesions of the genitalia caused by treponemal and chancroidal infection. Its medicines are long-acting penicillin by injection together with oral azithromycin.
Step 3: Reviewing the choices, scrotal swelling, urethral discharge and ano-rectal discharge each map to a separate kit colour, so they are excluded. The complaint that fits the blue pack is the presence of sores or ulcers over the genitals.
Step 4: Therefore the blue colour signals treatment of genital ulcer disease.
\[\boxed{\text{Genital ulcers}}\]