Pruritis, a common complaint in athletes, has many causes. In addition to the eczematous dermatoses previously discussed (see “A Closer Look At Eczematous Dermatitis In Athletes,” pg. 112, February issue), one should be aware of other equally important conditions that may cause itching in athletes. These conditions include infections, parasite infestations, insect stings or bites, allergic reactions and systemic conditions.
When a patient presents with a pruritic skin rash, there is often a great temptation to jump to a diagnostic conclusion of one of the eczematous dermatoses and immediately prescribe a topical corticosteroid preparation. However, it is important to obtain a thorough history of the pruritic condition and carefully observe the type and distribution of the presenting lesions.
Impetigo contagiosa is a common pruritic skin infection. Although it is most common in children, it also occurs frequently among groups of individuals, such as athletes, who have an increased risk of bruising injuries and who are in close contact with each other. The infection is spread by skin to skin contact or contact with a fomite piece of athletic equipment, particularly wrestling mats. Infection is more likely to occur in skin folds and areas subject to friction such as the arms and legs.
When these athletes have atopic or contact dermatitis, they have a greater risk for secondary impetiginization. This contagious superficial skin infection usually begins as a vesicular or pustular lesion that develops into exudative and crusting stages. Unless there is trauma or excoriation to the lesions, they usually heal without scarring. Staphylococcus aureus is the predominant organism isolated from impetiginous lesions. The combination of S. aureus and group A streptococcus is the next most common isolate. Staphylococcus pyogenes is less common as a causative agent with this condition.
Impetigo can present in one of two classic forms, the more common superficial type and the bullous type. Superficial vesiculopurulent pyoderma or common impetigo is most prevalent during the summer months and in areas with high humidity. Lack of hygiene and crowding, which occur in athletes’ locker rooms, are also predisposing factors. The typical lesion of superficial impetigo usually starts as an erythematous vesicle or papule in a traumatized area (scratch or insect bite). Then small vesicles may form and the lesion rapidly evolves to a thick, crusted lesion with a honey-color crust. When one removes the crust, the base of the lesion excretes a serous amber exudate and rapidly becomes encrusted again. These lesions are rarely painful and are often neglected for extended periods of time. Although regional lymphadenopathy is common, other systemic signs such as malaise, fever and toxic appearance are usually absent.
Bullous impetigo is much less common than superficial impetigo. The characteristic lesions are thin-walled bullae that are usually less than 3 cm in diameter. These lesions are prone to easy rupture. The fluid in the blisters may be a thin, amber liquid or an opaque pus that is white or yellow. Once the blister ruptures, the erythematous base dries quickly, forming a thin and shiny surface classically referred to as a varnish-like crust. The causative bacteria is usually S. aureus.
Treating impetigo involves the use of both topical and systemic antibiotics. Mupirocin 2% ointment is the most effective topical agent. One should clean the lesions with soap and water or peroxide before applying the ointment and a dry dressing. Multiple lesions often require oral antibiotics such as cefadroxil, cephalexin, dicloxacillin, amoxicillin/clavulanate or erythromycin. However, keep in mind that streptococcal species are showing increased resistance to erythromycin.
Prevention of impetigo is paramount in athletes. Cleanliness and proper treatment of superficial skin injuries is paramount. Other methods of prevention and thwarting the spread of impetigo include good personal hygiene, and meticulous cleaning of wrestling mats and other equipment with antiseptic agents. Due to the infectious nature of impetigo, the lesions should be clear of crusting before athletic participation is allowed.
Three similarly presenting pruritic skin infections of the foot include erythrasma, tinea pedis and candidiasis. They are caused by either a bacterial, fungal or yeast-like fungal organism, respectively.
Erythrasma is a bacterial infection involving the toe web area. This condition is frequently confused with fungal and candidal infections. The invading organism is Corynebacterium minutissimum. Predisposing factors include humidity, hyperhydrosis, heat, obesity and poor foot hygiene. This condition usually involves the third and fourth toe web spaces. Painful longitudinal fissures may occur in advanced cases. Erythrasma differs from fungal infections in that it has no advancing borders, is uniformly reddish brown and scaly, and fluoresces bright coral-red with Wood’s light.
Treatment involves extensive washing of the involved area with antibacterial soap and thorough drying after each wash. Topical 2% erythromycin solution is curative when patients apply it daily. In severe cases, it may be necessary to prescribe oral erythromycin 1 gram daily for seven days.
Tinea pedis presents as a dry, often pruritic, erythematous scaling of the soles. In severe cases, macerated, erosive or bullous lesions develop in the web spaces. Bacterial superinfection is common. One may confuse blistering (vesicular) tinea with contact dermatitis or dyshydrotic eczema. Tinea pedis is caused by a number of different fungi, most commonly Trichophyton rubra, Epidermophyton floccosum and Trichophyton mentagrophytes. The single most important test for diagnosing tinea pedis is direct visualization under the microscope of branching hyphae in keratinized material on the KOH wet mount preparation slide.
The three most common variants of tinea pedis one sees in athletes include the acute vesicular type, the chronic papulosquamous pattern and the chronic interdigital form.
Acute vesicular tinea pedis usually begins in the arch and leads to pruritic inflammation, which may be severe. Vesicles and blisters are common and may spread from the arch to the sides of the foot. This variant may be inactive during the cooler months with severe exacerbation during warmer or wetter months. The most common fungus cultured is T. mentagrophytes. Occasionally, one may encounter Epidermophyton floccosum. Treatment with most topical antifungal creams is usually effective.
Chronic papulosquamous tinea pedis is the most common variant of dermatophyte infection of the foot. A moccasin-type distribution on the foot consists of a dry, thick scale on the sole and sides of the foot. This infection is most commonly caused by T. rubrum. The hands may be similarly infected but it is very uncommon for both hands and both feet to show involvement. The common pattern is for both feet and one hand to be infected.
Topical treatment of chronic tinea pedis alone may not be sufficient to treat the more tenacious infections. A combination of local skin care, topical antifungal agents and systemic antifungal agents may be necessary to eradicate the condition. A topical corticosteroid may also be indicated to resolve the accompanying acute pruritis. Unfortunately, reappearance of the infection is common after stopping the therapy program.
Chronic interdigital tinea pedis usually starts in the toe web spaces and is characterized by scaling, maceration and itching. The infection commonly spreads from the interdigital web spaces to across the subdigital areas. T. mentagrophytes is commonly isolated from cultures from the interdigital web spaces. E. floccosum and T. rubrum may also be isolated. Treatment of the interdigital tinea pedis is very successful with topical antifungal solutions or creams that patients apply twice a day.
Candidiasis, also known as candidosis and monilias, is another infection that one may see between the fourth and fifth toes. It is characterized by maceration, desquamation and deep fissuring with a white rim of tissue. This infection is caused by a yeast-like fungus Candida albicans.
Factors that predispose a patient to candidiasis include: local occlusion resulting in heat, moisture and maceration; cutaneous trauma; a suppressed immune system; endocrinopathy such as diabetes mellitus; and preexisting ulcerations or fissures. Patients often complain of intense itching and burning.
When it comes to relieving the maceration, using warm water and Epsom salt foot soaks helps when one ensures through drying afterward. Applying topical antifungal creams and solutions to the web spaces two or three times daily usually provides rapid clearing of the infection.
One should consider parasitic infestations as possible causes when an athlete complains of severe itching. Two common infestations include cutaneous larva migrans and scabies. Cutaneous larva migrans (“creeping eruption”) is caused by hookworm larvae of various nematode parasites. The cat or dog hookworms, Ancylostoma braziliense and A. caninum, are the most common species in the southeastern United States, South America and many tropical countries. The adult nematodes are found in the intestines of dogs and cats. They deposit ova that are secreted in the feces. The ova hatch into larvae in the sand or soil where they are deposited. The larvae then penetrate human skin that comes into contact with them. This usually occurs as the athlete is sitting, standing or lying on the soil or sandy beach.
The condition is extremely common on the hands, feet, legs and buttocks region. One should suspect this condition among athletes who are involved in swimming or beach volleyball. Most infected patients complain of moderate to intense pruritis. The larva stays deep in the epidermis, directly ahead of the advancing tip of a serpiginous tract.
Treatment of cutaneous larva migrans begins with light freezing of the advancing border tip of the larva tract and the area of predicted travel of the larva with ethyl chloride spray. Using topical thiabendazole 10% aqueous solution is recommended for treating mild infections during the early stages of the infestation. Another option is oral thiabendazole (Mintezole), which is usually effective in resolving the pruritis in less than 12 hours. One may also employ topical corticosteroids to relieve severe urticaria if it is present.
Human scabies is a contagious disease caused by the itch mite, Sarcoptes scabiei var. hominis. Keep in mind that this itch mite produces a variety of cutaneous lesions, such as macules, papules, vesicles, pustules, bullae, nodules and scaling plaques, which one may confuse with the lesions of many other skin diseases. The pregnant female mite burrows into the stratum cornium and deposits her eggs and fecal material. The lesions produced are usually elevated and represent the active portion of the infestation.
The main symptom of scabies is intense pruritis. The itching is more pronounced in the evening or at night and after warm baths when mites appear to be more active. Scabies is usually contracted by close personal contact. The most prominent sites on the lower extremities are the interdigital spaces and soles of the feet.
Topical medications used for treating scabies include lindane (1% gamma benzene hexachloride), crotamine (10% N-ethyl-o-crotonotoluide), sulfur ointment (5% precipitated sulfur), permethrin, thiabendazole and coal tar.
Insect bites and stings can present as pruritic skin conditions in athletes. In most cases, the areas of itching are associated with the location of the insect attack. The athlete will usually give a history of such an episode and one can accordingly take appropriate measures to treat the condition (see “Recognizing And Treating Insect Bites And Stings In Athletes,” pg. 84, August 2004 issue).
Systemic allergic reactions resulting in pruritis require a thorough history as identifying the allergen is essential to providing appropriate treatment. Besides being subject to the same food and food-additive allergies that occur in the general population, athletes often use vitamins, food supplements and other performance enhancers that are potential allergens. A thorough history should include specific questions about the use of these and other over-the-counter products. Difficult cases may require allergy testing.
Finally, when attempting to diagnose a difficult case of generalized pruritis and excoriations without a specific history or primary lesion, one must consider the possibility of systemic disease. The prevalence of pruritis in systemic disorders ranges from quite high in renal disease and liver stasis to less frequent in thyroid disease and diabetes. Occult malignancies, especially of the lymphoreticular types and polycythemia vera, and iron deficiency anemia are also associated with pruritis. In addition, one should question athletes about anabolic steroid use. If they have used steroids, one should consider the possibility of liver disease.
Dr. Caselli (pictured) is a staff podiatrist at the VA Hudson Valley Health Care System in Montrose, N.Y. He is also an Adjunct Professor at the New York College of Podiatric Medicine and a Fellow of the American College of Sports Medicine.
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