Pigmentary discolorations may be divided into three main groups-(1) primary and idiopathic, (2) secondary or symptomatic., and (3) congenital.
The primary or idiopathic pigmentations result from the application of irritants which set up hyperaemia in some cases and in others not-as after the action of heat-or friction, or irritants, such as mustard plasters, or the pressure on a part, as by dresses, mechanical restraints, the friction of straps, and the following of certain handicrafts by which certain parts of the body are exposed to the sun or specially rubbed, as in masons. Scratching also will be followed in some cases by discoloration-this is seen in phthiriasis particularly.
Secondary or symptomatic stainings are those which follow in the wake of other diseases, or are due to disturbance of organs at a distance from the seat of discoloration that do not, in other words, constitute the essential disease, but are secondary to, or form only a part of, the essential diseases present in any given case. There are three groups of secondary pigmentations: 1. Those which follow in the wake of and occur in the same seat as certain skin eruptions; d2. Pigmentations occurring in connection with certain cachexias, the latter being associated with definite organic diseases of important internal organs; 3. Physiological pigmentations connected with uterine functional changes.
As regards congenital pigmentations, I need only say these are seen in moles and pigmentary naevi.
Those cases in which the pigmentation of the skin is at fault as the sole existing disease may be divided into two classes-those in which the pigment is deficient in quantity (Leucoderma, or Vitiligo), and those in which it is in excess (Melanoderma). These may be congenital or acquired, general or local. The seat of change is the rete mucosum.
Vitiligo, or leucoderma, is an affection characterized by circumscribed patches of skin, from which the pigment has disappeared to a greater or less extent. At the beginning the patches will be quite limited in extent, and affect by preference the face, neck, hands, and genitals. As a rule, however, they increase for a certain length of time, and neighboring patches coalesce. The borders of the spots are usually somewhat hyperpigmented, as if the pigment which had been removed from the centre had been simply deposited at the edges. This feature, however, is not always met with.
The course of vitiligo varies. With some individuals it reaches a certain degree of development, and then remains stationary for years; in others, it progresses indefinitely, and this so particularly when it affects the negro.
In perhaps the majority of cases there is a return of the natural pigment after the lapse of a few years, while in others the affection appears, lasts a few months and disappears, only to be followed by one or several recurrences. It may be absent during the hot months, and return during the cold ones.
The causes of vitiligo are unknown. It occurs in both sexes with apparently the same frequency, and usually without being preceded by any acute disease, or general failure of health. In fact, the majority of patients will complain of nothing except the unsightliness of the affection, which may pursue its course uncomplicated by trouble that can be attributed to it. There is no reason for believing that it ever shortens life. When we consider the permanency and progressive nature of some cases, we are utterly at a loss of account for this curious affection.
Treatment.-The old school acknowledge their incapacity to do anything in this affection. Our school is but little better off.
Locally, the pigmentation around the patch may be lessened by the use of strong acetic acid. Galvanism may prove serviceable. Internally the Sulphide of Arsenicum will be oftenest used with benefit. Natrum c., Nitr.ac., Sumbul and the Phosphide of Zinc may be studied.
This term of course means excess of pigment resulting in dark discolorations, but the altered tint of skin may be blue, yellowish, or black; hence the terms cyanoderma, xanthoderma, and melasma.
Melasma, or that condition in which the discoloration of skin is black in color, is general or partial. The latter is generally called melasma. It may be a physiological condition, as seen in the staining around the nipple and the linea alba in pregnancy; this condition may be excessive. The varieties of melasma are lentigo and ephelis.
Lentigo is known as freckles. The seat of the pigment deposit is the rete mucosum; it is often congenital, and of varying extent and distribution; generally, however, it consists of round yellowish spots, the size of split peas and less, not only on the parts exposed to the light, but also those covered by the dress. Lentigo occurs in those with fair skins, and particularly red-haired folk. There is no desquamation, no itching, and no heat of any kind in connection with freckles, which often disappear after puberty. Freckles do not depend upon seasonal change.
Lentigo may sometimes be made to disappear by an application of citric acid night and morning. One writer reports the application of emulsion of almonds, night and morning, to be the most satisfactory treatment, and advises its continuance until a slight amount of desquamation takes place. Another writer recommends the application of oleate of copper for the removal of freckles. Care should be exercised that a pure sample of the drug is obtained.
Rx. Cupric. Oleat., z3j.
M. Sig.: Apply twice a day.
The internal remedies are: Ferrum mag.-Spots resembling summer freckles on back of hands and fingers.
Kali carb.-Freckles on the face.
Lycopod.-Freckles on the left side of the face and across the nose.
Nitric acid.-Freckles on the chest; dark freckles.
Petroleum.-Freckles on the arms.
Phosphorus.-Freckles on the lower limbs.
Sepia.-Freckles on the cheeks.
Sulphur.-Freckles on the nose.
In this particular variety of discoloration the pigment deposit is excited by the sun’s rays. Sunburn consists of little dots the size of pins’ heads, which appear upon the parts of the body exposed to the influence of the sun, and are seen mostly in lymphatic subjects with delicate skins. Temporary benefit accrues from the use of local applications strong enough to cause exfoliation of the corneal cells. A one per cent. solution of mercuric bichloride and a ten percent. solution of calcium chloride are the lotions most commonly used.
Veratrum alb., Robinia and Kali carb. are useful internal remedies. Bufo is indicated when the face tans quickly.
Melasmic discoloration likewise occurs as the result of the action of local irritants-excessive scratching, strong lights, blisters.
Pigmentary Naevi.-These consist of collections of pigment in the rete and corium, and a certain amount of hypertrophy of the papilla at times. They may be furnished with hairs. Moles are of this nature.
Xanthoderma.-In this disease the pigmentary discoloration is yellowish. It is characteristic of certain races, and is due to some special condition of the coloring matter of the skin, molecular or chemical.
Cyanoderma, or blue discoloration, is different from colored sweat. It is a curiosity, if not, at least in the greater number of instances, a hoax.