A 12 years old child presenting with painless neck swelling in supraclavicular region which started discharging after few days. The most probable diagnosis -

Ans. is 'a' i.e., Scrofuloderma * All the given options can cause the given clinical picture. But, most common presentation of scrofuloderma is neck swelling with discharge.Scrofuloderma* Scrofuloderma is cutaneous tuberculosis due to direct extension of infection from an underlying tuberculosis present either in a lympnode, bone or a joint. Lesion has following characteristics: -# Starts as bluish painless swelling, which breaks open to form Sinuses -> Most common presentation is discharging sinuses.# Sinuses discharge caseus or watery material. If ulcers occurs, they are linear or serpiginous, with undermined edges, and a floor of granulation tissue.# Sites of predilection : -i) Cervical (most common), axillary & inguinal lymph nodes.ii) Legs (from tubercular osteomyelitis)iii) Skin over sternoclavicular joint (chest)About other options* Most common site of actinomycosis is angle of jaw (and in question, there is no history of discharge of sulphur granules).* Mycotic mycetoma and botromycosis are usually seen in foot (and they also discharge granules made of microcolonies of organisms).