Essentials of Diseases of the Skin. Henry Weightman Stelwagon

Leptus 277 Œstrus 278 Pulex Penetrans 278 Cimex Lectularius 278 Culex 279 Pulex Irritans 279 Table showing Relative Frequency of the Various Diseases of the Skin 280

DISEASES OF THE SKIN.

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ANATOMY OF THE SKIN

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      Fig. 1.

      Vertical section of the skin—Diagrammatic. (After Heitsmann.)

The Epidermis.

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      Fig. 2.

      c, corneous (horny) layer; g, granular layer; m, mucous layer (rete Malpighii). The stratum lucidum is the layer just above the granular layer. Nerve terminations—n, afferent nerve; b, terminal nerve bulbs; l, cell of Langerhans.

      (After Ranvier.)

The Blood-vessels.

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      Fig. 3.

      C, epidermis; D, corium; P, papillæ; S, sweat-gland duct. v, arterial and venous capillaries (superficial, or papillary plexus) of the papillæ. Deep plexus is partly shown at lower margin of the diagram; vs—an intermediate plexus, an outgrowth from the deep plexus, supplying sweat-glands, and giving a loop to hair papilla.

      (After Ranvier).

The Nervous and Vascular Papillæ.

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      Fig. 4.

      a, a vascular papilla; b, a nervous papilla; c, a blood-vessel; d, a nerve fibre; e, a tactile corpuscle.

      (After Biesiadecki.)

The Hair and Hair-Follicle.

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      Fig. 5.

      A, shaft of the hair; B, root of the hair; C, cuticle of the hair; D, medullary substance of the hair.

      E, external layer of the hair-follicle; F, middle layer of the hair-follicle; G, internal layer of the hair-follicle; H, papilla of the hair; I, external root-sheath; J, outer layer of the internal root-sheath; K, internal layer of the internal root-sheath.

      (After Duhring.)

SYMPTOMATOLOGY.

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      The symptoms of cutaneous disease may be objective, subjective or both; and in some diseases, also, there may be systemic disturbance.

      What do you mean by objective symptoms?

      Those symptoms visible to the eye or touch.

      What do you understand by subjective symptoms?

      Those which relate to sensation, such as itching, tingling, burning, pain, tenderness, heat, anæsthesia, and hyperæsthesia.

      What do you mean by systemic symptoms?

      Those general symptoms, slight or profound, which are sometimes associated, primarily or secondarily, with the cutaneous disease, as, for example, the systemic disturbance in leprosy, pemphigus, and purpura hemorrhagica.

      Into what two classes of lesions are the objective symptoms commonly divided?

      Primary (or elementary), and

      Secondary (or consecutive).

Primary Lesions.

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      What are primary lesions?

      Those objective lesions with which cutaneous diseases begin. They may continue as such or may undergo modification, passing into the secondary or consecutive lesions.

      Enumerate the primary lesions.

      Macules, papules, tubercles, wheals, tumors, vesicles, blebs and pustules.

      What are macules (maculæ)?

Variously-sized, shaped and tinted spots and discolorations, without elevation or depression; as, for example, freckles, spots of purpura, macules of cutaneous syphilis.

      What