Which of the following is/are tuberculides – a) Lichen scrofulosorumb) Lichen nichidusc) Lichen aureusd) Erythema nodosum

Now you must be thinking, why have I given erythema nodosum along with Lichen scrofulosorum, whereas in previous explanation only Lichen scrofulosorum was given as the answer. Read below, there will be no confusion. Tuberculids can be classified into two groups:- 1)   True (definite) tuberculids  Mycobacterium tuberculosis plays a major etiological role. Examples:- Erythema induration (Bazin's disease), papulonecrotic tuberculid, Lichen scrofulosorum. 2)   Facultative tuberculids Mycobacterium tuberculosis is one of the several etiological agents. Examples are:- Erythema nodosum.