TABLE 1.

Characteristics of early secondary lesions

Type of lesion	Characteristic appearance	Distribution on the body	Differential diagnosis
Macular	A pale pink, flat, and somewhat elliptical spot usually 4 to 8 mm in diameter. These may be violaceous in darker-skinned individuals. The central area is always more highly colored, whereas the periphery tends to blend into the surrounding skin. The reddish hue, due to localized hyperemia, resolves under pressure. Though probably the most common type of cutaneous lesion, these are often overlooked or misdiagnosed.	These lesions never appear on the face, in contrast to all other types of syphilids.	Erythema muliforme, seborrheic dermatitis, pityriasis rosea, tinea versicolor, tinea corporis, leprosy, measles, German measles, typhoid fever (Rose spots), toxic dermatitis, and dermatitis medicamentosa (drug rashes).
Small papular	Small, distinct, localized elevations of skin which are readily palpated. Solid, rounded, resistant to touch. Varies in color depending on skin pigmentation. May assume a pustular character with no exudate. In most areas such as the genital areas, the groin, and the axilla, they may appear in the form of flat condylomas.	Most common; favor the trunk. May appear on any part of the body, including flexor surfaces of the limbs, forehead, and temples. These lesions often border the scalp in the form of the so-called crown of Venus.	Erythema multiforme, psoriasis, pityriasis, keratosis, variola, lichen planus, papulonerotic tuberculid, urticaria pigmentosa, leprosy, mycosis fungoides, and adenoma sebaceum.
Follicular or pseudovesicular	Round or pointed papules which develop around the orifices of hair follicles and sweat glands. Vary in size from pinpoint to pinhead. Vary in color depending on skin pigmentation. Pigmentary deposits are frequent. Scaling often appears at the apex of the lesion. May also be involuted. Frequently larger in the genital and anal regions. Itching may be frequent due to sweat decomposition.	May appear on any part of the body. These lesions tend to group and are generally most abundant on the back, upper trunk, and arms. They are also frequently found on the thighs and face.	Lichen planus, lichen scrofulosorum, lichen nitidus, tineal dermatitis, seborrheic dermatitis, pityriasis rubra pilaris, keratosis pilaris, and lichen spinulosus.
Lichenoid	Flattened and angulated lesions resembling lichen planus.	May appear on any part of the body. These lesions also are generally most abundant on the back, upper trunk, and arms.	Lichen planus.
Vesicular	Pointed, very small, and ruptured only with difficulty. Reddish, raised base without an inflammatory areola. Often found in combination with small papular lesions. May constitute a transient intermediate type of lesion. Existence is questionable, as the vesicles are of short duration and often present for only a few hours.	May appear on any part of the body.	Erythema multiforme, psoriasis, pityriasis, keratosis, variola, lichen planus, papulonerotic tuberculid, urticaria pigmentosa, leprosy, mycosis fungoides, and adenoma sebaceum.
Psoriasiform	These lesions resemble those of psoriasis in color distribution and scaling. They differ from psoriasis in that the lesions never bleed when the scale is removed.	Found predominantly on the palms of the hands and soles of the feet. May also occur on the face, elbows, and knees. The scalp is exempt.	Psoriasis.
Corymbiform	Appearance of a nipple with a well-marked areola. These tend to be very unusual in that they are large lesions or plaques surrounded by a number of smaller lesions.	May appear on any part of the body.	No other dermatologic disease causes this type of lesion.