What do you mean by a patch of eruption?

A single group or aggregation of lesions or an area of disease.

When is an eruption said to be limited or localized?

When it is confined to one part or region.

When is an eruption said to be general or generalized?

When it is scattered, uniformly or irregularly, over the entire surface.

When is an eruption universal?

When the whole integument is involved, without any intervening healthy skin.

When is an eruption said to be discrete?

When the lesions const.i.tuting the eruption are isolated, having more or less intervening normal skin.

When is an eruption confluent?

When the lesions const.i.tuting the eruption are so closely crowded that a solid sheet results.

When is an eruption uniform?

When the lesions const.i.tuting the eruption are all of one type or character.

When is an eruption multiform?

When the lesions const.i.tuting the eruption are of two or more types or characters.

When are lesions said to be aggregated?

When they tend to form groups or closely-crowded patches.

When are lesions disseminated?

When they are irregularly scattered, with no tendency to form groups or patches.

When is a patch of eruption said to be circinate?

When it presents a rounded form, and usually tending to clear in the centre; as, for example, a patch of ringworm.

When is a patch of eruption said to be annular?

When it is ring-shaped, the central portion being clear; as, for example, in erythema annulare.

What meaning is conveyed by the term "iris"?

The patch of eruption is made up of several concentric rings. Difference of duration of the individual rings, usually slight, tends to give the patch variegated coloration; as, for example, in erythema iris and herpes iris.

What meaning is conveyed by the term "marginate"?

The sheet of eruption is sharply defined against the healthy skin; as, for example, in erythema marginatum, eczema marginatum.

What meaning is conveyed by the qualifying term "circ.u.mscribed"?

The term is applied to small, usually more or less rounded, patches, when sharply defined; as, for example, the typical patches of psoriasis.

When is the qualifying term "gyrate" employed?

When the patches arrange themselves in an irregular winding or festoon-like manner; as, for instance, in some cases of psoriasis. It results, usually, from the coalescence of several rings, the eruption disappearing at the points of contact.

When is an eruption said to be serpiginous?

When the eruption spreads at the border, clearing up at the older part; as, for instance, in the serpiginous syphiloderm.

RELATIVE FREQUENCY.

Name the more common cutaneous diseases and state approximately their frequency.

Eczema, 30.4%; syphilis cutanea, 11.2%; acne, 7.3%; pediculosis, 4%; psoriasis, 3.3%; ringworm, 3.2%; dermat.i.tis, 2.6%; scabies, 2.6%; urticaria, 2.5%; pruritus, 2.1%; seborrh[oe]a, 2.1%; herpes simplex, 1.7%; favus, 1.7%; impetigo, 1.4%; herpes zoster, 1.2%; verruca, 1.1%; tinea versicolor, 1%. Total: eighteen diseases, representing 81 per cent. of all cases met with.

(These percentages are based upon statistics, public and private, of the American Dermatological a.s.sociation, covering a period of ten years. In private practice the proportion of cases of pediculosis, scabies, favus, and impetigo is much smaller, while acne, acne rosacea, seborrh[oe]a, epithelioma, and lupus are relatively more frequent.)

CONTAGIOUSNESS.