# Skin Diseases of Children/Naevi, Pigmented and Hairy

Plate VIII.
Nævus pilosus.
From the collection of Photographs of Dr. George Henry Fox.
NAEVI, PIGMENTED AND HAIRY.
The term naevus signifies a spot or blemish upon the skin. It is usually a congenital affection, although certain forms of skin disease to which the term nsevus is commonly applied may occur in youth or later in life. Many nsevi, especially of the pigmented and hairy variety, exist at birth, but are almost imperceptible, and only become noticeable when they develop, as they are apt to do, after the age of puberty.
The term nsevus includes affections of widely different pathological character in which hypertrophy is the only common element. They may be classed as iibrous, pigmented,. hairy, and vascular nsevi. The fibrous or hypertrophic nsevus frequently occurring upon the face in the form of a small, rounded, and non-pigmented tumor or mole is peculiar to adult life, but the pigmented and hairy forms of nsevus are common in childhood and often require treatment at an early age.
Naevus pigmentosus is the result of an excessive deposit of pigment granules in the mucous layer of the skin. It differs from a freckle or chloasmic discoloration (which are acquired affections and liable to disappear spontaneously) in appearing at or soon after birth and being permanent. The pigmentary nsBAois varies greatly in color and size. It may be yellowish or of a deep-brownish hue. It may be no larger than a pin's head, in which case it is apt to be multiple, or it may cover a portion of the body larger than the hand. The face, neck, and back of the hand are favorite sites, but it may appear on the trunk and extremities. It is sometimes flat and smooth, like a freckle, but may become elevated and warty in certain cases, when the term nsevus verrucosus is applicable.
In many cases of extensive pigmentary nsevus, whether smooth or elevated, "we find a growth of fine or coarse hair upon the surface. When this is more marked than the pigmentation the affection is called nsevus pilosus. The hairy nsevus is often ​a small oval patch (as in the plate), and from its size and shape its origin is frequently ascribed to some maternal impression—e.g., the mother having been frightened by a mouse. Often the hairy scalp appears to extend over the temple or upon one side of the forehead, as in Fig. 28, and not infrequently it is seen
Fig. 28.
upon the cheek beneath the eye or involving both lids and vicinity, as in Fig. 29.
In rare cases a large extent of cutaneous surface is affected, and the whole trunk may appear as though covered with fur instead of normal skin (Fig. 30). The lumbar or pelvic region is also apt to be the seat of the hairy nævus, which in some cases ​has suggested a resemblance to "bathing-tights." The congenital growth rarely increases in extent, except as the body grows larger, but often the pigmentation becomes more pronounced and the hair begins to grow coarser in adult life. The development of small hairy moles upon the face of elderly
Fig. 29.
women, especially those suffering from hypertrichosis, is very frequently noted.
In the treatment of the pigmentary mole, acids or the electrolytic needle may be employed. For small, round, dark spots on the skin a minute drop of nitric acid, applied with a wooden toothpick, will often suffice to remove the blemish. In case of larger pigmented patches, either smooth or covered with fine hair, the surface of the skin may be dotted with the acid; but ​extreme caution must be used to prevent ulceration, lest scars be left which would be far more disfiguring than the nævus itself. With children old enough to bear a little pain without crying, the pigmented spots may be blistered by touching them with the point of the electrolytic needle or by passing it superficially through the epidermis.
In nævi of small or moderate size covered with coarse hair
Fig. 30.
the electrolytic needle may be used, as in the treatment of hypertrichosis, and a fine result attained through patience and perseverance. In the Journal of Cutaneous Diseases for May, 1893, the writer has reported a case of extensive hairy and verrucous nævus involving the right cheek and lower eyelid, which was completely removed by means of electrolysis. The treatment consisted in carefully passing a fine, flexible steel ​needle, connected with the negative pole of a galvanic battery, through the most superficial portion of the growth, the circuit being completed by the patient grasping a moist sponge attached to the positive electrode. This was repeated until the electrolytic destruction of tissue reduced the growth to the level of the surrounding skin, removed the pigmentation, and to a certain extent destroyed the hypertrophied hair follicles. The slight growth of hair which persisted after the affected skin had become smooth and comparatively normal in color was destroyed by the introduction of the electrolytic needle into each separate follicle, according to the method employed in the treatment of superfluous hair. The young man now presents not the slightest deformity of the eyelid, and scarcely a trace, upon close inspection, of the dark, warty, and hairy growth which formerly attracted attention wherever he went and was the source of great mortification.