(Fever blister; Cold sore)
Definition. An acute, inflammatory, non-contagious disease of the skin, characterized by the formation of grouped, closely aggregated vesicles upon an erythematous base.
Symptoms. There are two forms: herpes facialis, and herpes genitalis, so called because of their location.
Herpes facialis may be located upon the face, neck or ears, though commonest about the mouth or nose. When occurring upon the tongue or mucous membrane of the mouth, they are commonly called canker sores; when associated with fever, fever sores, herpes febrilis, and they are know as cold sores. After more or less distinct sensations of heat, tension, pricking, or itching at the point of attack, a sensitive swelling appears quite suddenly, which in a short time is transformed into papules, and a few hours later into vesicles. These are pin- head to pea-sized, full of transparent, serous fluid and arranged in one or more irregular groups of a dozen or less, which may coalesce ad form blebs. Within a few days the vesicles become opaque or yellowish, may dry up without rupture and form yellowish, blackish crusts, which fall off in a few days, leaving the skin intact or the skin may remain slightly reddened or stained for a longer period. If the crusts are are torn off and irritated, an oozing surface is exposed. Occurring on the mucous surfaces, herpes is not usually seen in the papulovesicular stage, but only after the epithelia have been shed, leaving sharply defined, grayish-white patches, before referred to as canker sores.
Herpes genitalis (herpes progenitalis) occurs on the external genital organs of both sexes. In men, the most common seat is on the mucous surface of the prepuce, but it may occur upon the outer part, or at any point on the skin of the penis, the glans or even in the meatus. In women, it is often situated on the labiae, clitoris, and mons veneris, but may appear on the perineum, anal, vaginal or genitocrural regions. The process only differs from herpes facilis as it is modified by heat, friction or pressure. But on the mucous surfaces, vesiculation is often attended with some swelling. If, however, the denuded spots are irritated by repeated coitus, caustics, etc., ulceration may follow, even lasting for weeks, masking the primary affection, and often attended with inflammation of the inguinal glands.
Etiology and Pathology. Herpes facialis results from gastrointestinal disorders, in the course of many cases of pneumonia, malaria and cerebrospinal meningitis, and in a few cases of typhoid fever, influenza, tonsillitis and diphtheria, or it may come from such external irritants as wind or sun rays. Herpes genitalis frequently originates from previous venereal disease. It is more common in prostitutes not only because of the greater prevalence of venereal disease among them but also because of more frequent local irritations. In may be caused by excessive sexual intercourse or by menstruation in women.
It is reasonable to explain the occurrence of herpes simplex on the ground that an acquired susceptibility of the sensory nerves of the surrounding parts exists to such an extent that unusual or even ordinary local factors excite of reflex action in the neighboring sympathetic ganglia. While the structural nerve changes in herpes simplex are not definitely determined, they closely resemble those found in herpes zoster. It is probable than in those instances accompanying infectious diseases there is a toxic effect upon the nerve structures by some developed toxin.
Diagnosis. Herpes facialis might be mistaken for eczema, impetigo or herpes zoster. From eczema it is easily distinguished by its larger vesicles, tendency to dry up without rupture or continuous weeping, and its short course. The resemblance to impetigo would be only apparent after crusts had formed. In herpes they are less elevated, which, together with the history of development from grouped vesicles, would settle the diagnosis. Zoster is preceded or attended with sharp, neuralgic pains, is situated on the lines of nerve distribution (rarely on the face), is nearly always unilateral and of longer duration, and does not tend to recur.
Herpes genitalis might be mistaken for the primary sore of syphilis, but a chancre is usually solitary, indurated, attended with inguinal adenitis, with a slight discharge and is slow in evolution. Chancroid is destructive in tendency, autoinoculable, and produces induration and sometimes suppuration of the glands of the groin, while herpes, often without glandular swelling, and usually can be made to discharge serous fluid by pressure.
Prognosis and Treatment. The outlook is good for immediate recovery, and has little significance when occurring in the course of an acute disease, but the tendency to recur is marked in the ordinary types. In the case of herpes of the genitals, the fact that such an eruption opens the possibility of venereal infection should be remembered in cases of probable exposure, both as regards diagnosis and prognosis.
In cases of herpes facialis, protection may be given to the affected skin and resolution hastened by painting the patches with collodion, or if crusts have formed, by removing the same with sweet oil, followed by the application of some simple powder like aristol or boric acid.
Absolute cleanliness is essential in herpes genitalis. This may be accomplished by washing the parts with soap and water, immediately followed by the application of powdered boric acid, aristol or calomel, or if friction is imminent, a 10 per cent. ointment of boric acid or aristol may be used. If, as is often the case, the condition is recurrent an effort should be made to correct the predisposition, and prophylaxis may become a most important element of treatment. This is particularly true of the genital type, were the local use of tannin and brandy or aromatic wine, plus a sexual hygiene, will prevent a genital congestion and thus a recurrence.
Internal remedies based on causal or related symptoms are often all sufficient and are the most important item of treatment. See indications for Arsenicum, Cantharis, Carbo veg., Cistus, Clemat., Cornus circ., Crot. tig., Dulcamara, Hepar, Nat. mur., Sepia, Sul., Terebinth., Thuja, and Urtica urens.