The rash at the beginning of syphilis is usually a hard chancre that develops on the external genitalia, starting as a small red spot and progressing rapidly, which may be followed by a syphilitic rash that lacks specificity after the chancre has subsided.
The typical chancre begins as a small erythematous spot that rapidly develops into a painless inflammatory papule that enlarges within a few days to form a hard nodule, with surface necrosis, forming a single 1- to 2-centimetre-diameter, round or oval, painless ulcer, with a clear border, a peripheral oedematous and elevated, fleshy-red base, and cartilaginous hardness to touch with a plasma secretion on the surface.
If stage I syphilis is untreated or incompletely treated, the lesions may appear 3 to 4 weeks after the noma has subsided or at the same time as the noma, presenting a syphilitic rash that lacks specificity, and may be characterized by erythema, papules, pemphigus, plaques, nodules, pustules or ulcers, and are often predominantly of one type of lesion, most of which are generalized, itch-free or mildly itchy.
If there is any discomfort, one should go to the hospital for examination and treatment as soon as possible. If syphilis is diagnosed, treatment should be standardized as early as possible to avoid rapid progression and serious complications.