Many suspected etiologic factors have been reported to cause<unk> . * Infections: bacterial (including Bacillus Calmette–Guérin (BCG) vaccination, haemolytic Streptococci, legionellosis, leprosy, Neisseria meningitidis, Mycobacterium, Pneumococcus, Salmonella species, Staphylococcus species, Mycoplasma pneumoniae), chlamydial. * Fungal (Coccidioides immitis) * Parasitic (Trichomonas species, Toxoplasma gondii), * Viral (especially Herpes simplex) * Drug reactions, most commonly to: antibiotics (including, sulphonamides, penicillin), anticonvulsants (phenytoin, barbiturates), aspirin, modafinil, antituberculoids, and allopurinol and many others. * Physical factors: radiotherapy, cold, sunlight * Others: collagen diseases, vasculitides, non-Hodgkin lymphoma, leukaemia, multiple myeloma, myeloid metaplasia, polycythemia<unk>  minor is regarded as being triggered by HSV in almost all cases. A herpetic etiology also accounts for 55% of cases of<unk>  major. Among the other infections, Mycoplasma infection appears to be a common cause. Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent<unk>  eruption.
Erythema multiforme
Serum sickness
Streptococcal intertrigo
Heat urticaria
Urticarial erythema multiforme
Cold urticaria
Blister beetle dermatitis
Cutaneous larva migrans