DERMATITIS VENENATA

Rhus poisoning. Ivy poisoning.

Dermatitis venenata is a generic term which designates a great number of dermic irritations caused by contact with deleterious substances, among which are many common drugs such as arnica, mercurials, iodoform, turpentine, tar, etc., many chemical reagents, numerous dye-stuffs and materials handled in trade. But the most prolific source of the disorder in this country is the emanation of certain plants especially those of the rhus genus, the rhus toxicodendron or poison-ivy, the rhus diversiloba or poison-oak, the rhus venenata or poison-sumac, -dogwood or -elder, and other species of less common occurrence. Individuals differ in susceptibility, many can handle the plants with impunity while others suffer from the slightest touch. The parts of the skin involved are the exposed portions which come in contact with the leaves and the regions to which the poison may be transferred by the hands. The symptoms develop usually after a few hours. A feeling of warmth and itching first attracts the patient's attention to the affected area which then appears erythematous and slightly swollen. Sometimes wheals are present. All the symptoms increase gradually in severity. The itching and burning may become intense and the swelling very pronounced, especially wherever the tissues are lax, as upon the face and scrotum. Soon

myriad small vesicles appear, discrete but closely
crowded on the reddened skin and some may show
beyond the limits of the erythema. Comparatively
few run together to form larger blebs. Their con-
tents are clear or only slightly turbid. As they
rupture the serous oozing becomes profuse. After
a few days the acute symptoms begin to subside.
The redness decreases, the lesions dry to crusts
which fall off and leave no scars and the skin con-
dition is gradually restored to normal. In severe
cases the dermatitis may give rise to a persistent
and sometimes recurrent eczema. DIAGNOSIS:
The points to be considered in differentiating the
condition from vesicular eczema are, the history of
exposure to contact with plants, the size of the
vesicles and their slight tendency to rupture, the
absence of papules, the nonstickiness of the exu-
date, and the rapid involution of the lesions.
TREATMENT: The substance which causes the
irritation is soluble in alcohol and is precipitated by
lead acetate, therefore bathing the exposed regions
of the skin with a saturated alcoholic solution of
lead acetate will destroy the poison and prevent the
development of a dermatitis. Parts already inflamed
should be covered with cloths kept wet with a lotion
containing three per cent each of zinc oxid and
calamin.

HST.OOO.OO.I