Pinta

Introduction

Pinta, also called puru-puru or carate, is a relatively benign (mild and non-progressive) skin disease, caused by bacteria called Treponema carateum. Other species of Treponema are responsible for yaws and syphilis in humans, but unlike these conditions, pinta only affects the skin. Pinta is only found in scattered rural areas of Central and South America. It was first described in the 16th century in Aztec and Caribbean Amerindians. The prevalence of pinta is decreasing; in the 1950s about 1 million cases of pinta were reported, currently only a few hundred cases are reported per year.

Pinta primarily affects children and young adults. Although the exact mode of transmission is unknown, pinta is probably transmitted by direct skin or mucous membrane contact. Insect bites have been implicated in transmission, since they break the skin.

Clinical features

Pinta is classified into an early and a late stage. After an incubation period of 2 to 3 weeks the initial skin lesion develops. This lesion is a papule (small raised bump) that slowly enlarges to become an itchy, red, scaly plaque (large, flat lesion). The areas most commonly affected are exposed skin on the top of the feet, legs, back of the hands, and the forearms. Lymph nodes near affected skin may become enlarged, but the patient does not develop any systemic symptoms.

Late lesions, called “pintids”, occur after 6 months to 3 years. Pintids are large areas of abnormal pigmentation, and can be both achromic or hyperpigmented. Lesions may appear red, white, blue, violet, or brown.

Diagnosis

• The diagnosis is commonly made based upon the appearance of the lesions.
• T carateum cannot be distinguished from other Treponema species that cause yaws and syphilis with commercially available laboratory tests.
• Dark field microscopy of swabs taken from early lesions may reveal treponemes.
• Serological blood tests will be positive for syphilis.
• Biopsy of the lesions may reveal characteristic microscopic changes. In early lesions, treponemes may be demonstrated using silver stain.

Treatment

Pinta is treated with benzathine penicillin. Other useful antibiotics include tetracycline or erythromycin. Skin lesions become non-infectious within 24 hours of treatment. Early lesions heal within 6 to 12 months, but pigmentary changes persist in late lesions.