(Yaws; Polypapilloma tropicum; Pain)
Definition – An endemic, markedly contagious disease, characterized by papules, nodules and tumors which develop into exudating, raspberry-like tubercles or patches.
Symptoms – The stage of incubation of this disease lasts from one to two weeks during which there may be loss of appetite, fever, excessive sweating, indefinite pains and languor. Adults often fail to show these prodromata. The stage of eruption may be preceded by a dry, scaly condition, especially on the trunk and legs. These lesions may coalesce and cover large portions of the body. Some may disappear while others remain, and it is upon the latter that the real eruption develops. This indefinite stage is followed by the so-called primary stage in which a papule appears at the point of inoculation. This papule is hard, itchy, and as it gradually enlarges, presents a depressed yellow spot in its center. The primary lesion may be pustular instead of papular. In any event it is generally extragenital, most commonly appearing on the hands and face in children and on the extremities in adults.
During the development of this initial lesion or following it, the so-called secondary stage of the disease may be noticed. This consists of pin-head-sized, conical papules with yellowish points, surrounded by a red areola. The eruption may be limited to one region or it may be widely distributed. The favorite locations are the face, neck, arms and genitalia. It is least abundant upon the trunk. The papules enlarge to nodules with appreciable increase in breadth and become covered with yellow crusts. These fall away leaving exposed a papillomatous surface from which exudes a yellowish, offensive and adhesive fluid. These larger growths are often smaller at the base, hard and freely movable with the skin, and after one or two months’ development have been compared in appearance to a raspberry, strawberry or mulberry. A tertiary stage of yaws has been noted and is present in a limited number of cases in the form of ulcerations, gummata, enlargements of the long bones, synovitis and other changes bearing a resemblance to tertiary syphilis. Itching of varying degree may be present but the yaw itself is not sensitive or painful.
Etiology and Pathology – This condition is endemic in certain tropical countries especially on the west coast of Africa. It is contagious, inoculable and one attack usually produces an immunity. It is found chiefly in the black race. Both sexes and all ages may be attacked, but particularly the children. The point of inoculation is usually on an exposed part and nearly always extragenital. It may be acquired by direct or indirect contact or through the bites of flies or other insects. Yaws is undoubtedly due to a microorganism, but the findings are not uniform. Castellani named his organism the Spirocheta pertenuis which closely resembles the parasite of syphilis. There are a few observers who believe this disease to be syphilis modified by local conditions, but experiments with apes and clinical observations have shown that syphilis does not protect from yaws, nor vice versa. The pathological findings demonstrate that this is an infective granulomata presenting cellular infiltration in the cutis, excessive hypertrophic elongation of the papillae and overgrowth and hyperkeratosis of the epidermic cells.
Diagnosis – The limitation of this affection to tropical regions, the peculiar evolution of its lesions, duration, etc., clearly distinguish it from most cutaneous diseases. The supposition that is closely resembles syphilis is denied by those who have had opportunity to observe both diseases in detail. Daniels, from observation of the disease in Fiji, says “the eruption has no resemblance to primary or secondary syphilis and shows none of the associated lesions and, if considered as a tertiary manifestation, there are neither primary nor secondary stages, for throughout it shows lesions of exactly the same character. The early lesion of yaws is not indurated like a chancre, does not tend to become phagedenic and is rarely genital. In the next stage it is not symmetrical or polymorphous like secondary syphilis and the mucous membranes are never affected until later, sometimes years after.