Sand Fly Skin Sores: Prevention and Care

If a small bump appears on the face, arm or leg, slowly turns into an open sore and refuses to heal over weeks, it may not be an ordinary skin infection. In several parts of the world it can be cutaneous leishmaniasis, a disease carried by a tiny biting insect.

What causes it?

Cutaneous leishmaniasis is caused by parasites passed on through the bite of infected female phlebotomine sand flies. It is the most common form of leishmaniasis. According to WHO, it causes skin lesions, mainly ulcers, on the exposed parts of the body, and these can leave life-long scars and cause serious disability or stigma.

WHO estimates 600 000 to 1 million new cases occur worldwide each year, though only around 200 000 are actually reported. About 95% of cases happen in the Americas, the Mediterranean basin, the Middle East and central Asia, and WHO's Eastern Mediterranean Region alone accounts for 80% of cutaneous leishmaniasis cases reported worldwide.

Is it a problem in Pakistan?

Yes. WHO states that Pakistan carries one of the highest burdens of major vector-borne diseases, naming malaria, leishmaniasis, dengue, chikungunya and Crimean-Congo haemorrhagic fever. WHO's regional office has documented outbreaks in Pakistan for years: in 1997 in a camp in Dir district, where 38% of 9200 residents had active lesions and 13% more had scars, and from February 2001 onwards around Larkana and Dadu in Sindh, where the disease is now described as endemic. Cases have also been treated in Balochistan.

How do you avoid sand fly bites?

Sand flies are much smaller than mosquitoes, which means they can get through smaller holes, including ordinary mosquito netting. Protection has to allow for that.

• Sleep in a well-screened or air-conditioned room where you can.
• If that is not possible, use a fine mesh bed net and tuck the edges under the mattress. An insecticide-treated net is better still.
• Wear long-sleeved shirts, long trousers and socks, and tuck your shirt into your trousers.
• Use insect repellent on skin that is not covered, and also under the ends of sleeves and trouser legs. Products containing DEET are generally the most effective.
• Clothing, screens, curtains and sheets can be treated with insecticide. Treated clothing needs re-treating after about five washes.
• Spray living and sleeping areas with insecticide to kill insects indoors.

At community level, WHO recommends insecticide spraying, insecticide-treated nets, environmental management and personal protection together. One household acting alone gets less benefit than a neighbourhood that acts together, so support local spraying campaigns when they come.

How is it treated?

Leishmaniasis is a treatable and curable disease, but treatment is not something you can arrange yourself. It has to be prescribed and supervised by a health worker, because the right treatment depends on the type of parasite, the number and position of the sores, and your general health. Do not put home remedies, hot objects, acids or unlabelled creams on the sore. Those do not cure the infection and can make the scar much worse.

WHO says access to medicines has improved significantly through a WHO-negotiated price scheme and a medicine donation programme, so ask at a government hospital or district health office if a private clinic tells you treatment is unaffordable. WHO also stresses that early diagnosis and effective, prompt treatment reduce how much disease is circulating and prevent disability and death. In practice, going early is what protects your skin.

When to see a doctor

See a doctor if a skin sore has not healed after a few weeks, if a bump slowly grows into an open ulcer, or if new sores keep appearing. Go sooner, not later, if the sore is on the face, near the eye, nose, lip or ear, because scarring there causes the most lasting harm, or if sores are large, numerous or spreading.

Also see a doctor if the sore becomes hot, painful and swollen, starts producing pus, or you develop a fever alongside it, as that can mean a second bacterial infection has set in. If someone becomes seriously unwell with a spreading skin infection and fever, call Rescue 1122 where available, or go to the nearest hospital emergency department.