5. Parasitic Skin Infections

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The ﬁnal chapter in the section on sports-related skin infections in athletes reviews the several parasites that infest humans. These infestations are more unusual than the infections discussed in previous chapters and rarely have long- term sequelae. Nonetheless, contracting these infections just prior to competition can severely limit an athlete’s ability to participate. Scabies and lice are the two conditions that athletes contract directly from other athletes. Athletes acquire cutaneous larva migrans from the venue in which they compete.

Cutaneous Larva Migrans Epidemiology

One case of cutaneous larva migrans in a world-class volleyball player is reported. The parasite’s larva causing this condition resides in the sand and attaches to barefoot athletes (Biolcati and Alabiso, 1997). Ancylostoma braziliense causes cutaneous larva migrans.

Clinical Presentation

A pruritic, well-deﬁned, linear, erythematous plaque is seen on the lower extremities (Figure 5-1).

Diagnosis

The diagnosis is made based on the clinical ﬁndings. Peripheral eosinophilia and secondary bacterial infection may be present. Migratory pulmonary inﬁl- trates occur, so a chest radiograph is recommended.

Treatment

Topical or oral thiabendazole 400 mg twice per day for 5 days clears the infestation. The athlete should not have any pruritus after 2 days.

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Prevention

Protective footwear should be worn when the athlete is playing in sand known to harbor the parasite. The areas where beach volleyball matches occur should be clean and clear of animal feces, which can contain eggs that produce the larva.

Cutaneous Myiasis Epidemiology

A swimmer developed cutaneous myiasis after donning swimming trunks that had been left to dry outside in Africa (Jacobs and Orrey, 1997). The tumbu ﬂy (Cordylobia anthropophaga) had deposited its eggs and larvae within the bathing suit.

Figure 5-1. Serpiginous and erythematous plaques with cutaneous larvae migrans on the foot.

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Several tender, pruritic, erythematous nodules with punctum developed on the buttocks. The swimmer complained of tender lymphadenopathy and malaise.

Diagnosis

The diagnosis is made based on the clinical ﬁndings. Biopsy reveals the larvae. Examination of the swimming trunks can reveal numerous 1-mm eggs.

The differential diagnosis primarily includes furunculosis.

Treatment

Multiple therapies for cutaneous myiasis include surgical excision or application of petroleum jelly, beeswax, and mineral oil to suffocate the larvae.

Prevention

In endemic areas, swimming suits should not be left to dry in the open environment.

Pediculosis Epidemiology

Any athlete with close skin-to-skin contact is at risk for developing scabies, but wrestling is the one sport that has dominated the literature and guideline recommendations. Based on data from the National Collegiate Athletic Association injury surveillance system (NCAAISS), 0.1% of all skin infections in collegiate wrestlers between 1991 and 2003 were caused by pediculosis.

86 Sports Dermatology

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Pediculosis corporis (body lice), pediculosis capitis (head lice), and pediculosis pubis (genital lice) are the three types of lice that may infect the athlete (Figure 5-2). Once exposed, the athlete develops the condition in up to 10 days.

Athletes complain of pruritus in the affected area.

Diagnosis

The diagnosis is made upon direct visualization of the nits or live lice. The lice can be seen on the hair or on the seams of clothes.

Treatment

Affected athletes must apply permethrin 5% cream, lindane shampoo, or petrolatum to the affected area once per day for 1 week. All clothes and equipment worn and bed sheets slept upon within 3 to 5 days prior to treatment should be laundered and dried in a hot cycle. If laundering is not possible, then at-risk Figure 5-2. Slender moving organisms populate the hair of an athlete with pediculosis capitis.

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material should be placed in an airtight bag for 3 to 5 days. Athletes must avoid upholstered furniture that they sat upon within the past 3 to 5 days. Intimate contacts require treatment.

Prevention

Athletes with lice should not participate in sports with plentiful skin-to-skin contact. According to NCAA rules, wrestlers must be adequately treated before competition. Athletes must be without lice. The ultimate disposition of the athlete is decided by the certiﬁed athletic trainer or physician at the time of skin check.

Scabies

Epidemiology

Any athlete with close skin-to-skin contact is at risk for developing scabies, but wrestling is the one sport that has dominated the literature and guideline recommendations. Based on data from the National Collegiate Athletic injury surveillance system (NCAAISS), 0.5% of all skin infections in collegiate wrestlers between 1991 and 2003 were caused by scabies. Sarcoptes scabiei, the mite that causes scabies, burrows through the epidermis and deposits its feces and eggs.

Once exposed to another affected athlete, the competitor develops lesions within 3 to 4 weeks. Athletes develop intense pruritus that worsens in the evening. Lesions appear on the arms, hands, and groin (Figure 5-3) and progress to include the trunk (Figure 5-4) and lower extremities. Most of the lesions on the body reﬂect a subacute dermatitis related to the host immune system’s reaction to the mite. Extremely careful examination of the volar aspects of the wrist (Figure 5-5), interdigital spaces, and elbows reveal subtle, thin, linear, scaling plaques with or without erythema. The presence of a barely visible black speck is the burrowing organism.

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Figure 5-3. Reactive erythematous papules occur in scabies, not uncommonly in the genital region.

Diagnosis

Not uncommonly, both athletes and nonathletes with scabies are misdiag- nosed. The differential diagnosis includes atopic dermatitis, contact dermatitis, and eczematous drug eruption. It is incumbent upon the clinician to perform a scabies preparation.

The best manner in which to perform a scabies preparation is as follows.

The clinician dips a no. 15 blade into mineral oil and places a drop of mineral oil on a microscopic slide. The liner plaque should be scraped in one direction toward the end with the black speck. After three or four continuous scrapes, the clinician should rub the blade’s contents on the microscopic slide in the area of the drop of mineral oil. This process should be repeated several times for as many burrows as can be identiﬁed on the athlete. Increasing the number of

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Figure 5-5. Extremely careful examination of the volar aspects of the wrist and elbows to detect burrows is critical.

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burrows examined increases the chance of a positive preparation. A coverslip should be placed upon the mineral oil and the slide examined under low-power magniﬁcation. A positive mineral oil preparation reveals live or dead mites. Eggs and feces (scybala) also conﬁrm the diagnosis (Figure 5-6).

Treatment

Affected athletes must apply permethrin 5% cream applied to all skin sur- faces from the neck to the toes at bedtime. They should not neglect the umbili- cus, groin, interdigital areas or beneath the nails. The cream should be washed off in the morning. The same therapy should be repeated 1 week later. Alterna- tively, 200µg/kg oral ivermectin can be taken, with a repeat dose recommended 1 to 2 weeks later. All clothes and equipment worn and bed sheets slept upon within 3 to 5 days prior to treatment should be laundered and dried in a hot cycle.

If laundering is not possible, then at-risk material should be placed in an airtight bag for 3 to 5 days. Athletes must avoid upholstered furniture that they sat upon within the past 3 to 5 days. Intimate contacts require treatment.

Pruritus resolves very quickly. Unfortunately, in rare cases, pruritus persists in an athlete. The scabies organism is generally killed, but the pruritus is a per- sistent hypersensitivity reaction that may require topical or oral steroids.

Figure 5-6. Presence of the scabies organism determined by microscopic examination conﬁrms the diagnosis. The small brown clumps represent scybala (scabies’ feces).

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Prevention

Athletes with scabies should not participate in sports with extensive skin-to- skin contact. According to NCAA rules, athletes must have a negative scabies preparation before competition. The ultimate disposition of the athlete is decided by the certiﬁed athletic trainer or physician at the time of skin check.

Bibliography

Biolcati G, Alabiso A. Creeping eruption of larva migrans: a case report in a beach volley athlete. Int J Sports Med 1997;18:612–613.

Jacobs P, Orrey L. Micro-abscesses in the swimming trunk area. S Afr Med J 1997;

87:1559–1560.