Itching in Active Patients: Causes and Cures
Steven M. Leshaw, MD
Dermatology Series Editor: Robert S. Scheinberg, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 26 - NO. 1 - JANUARY 98
In Brief: The cause of pruritus can be as benign as dry skin or as serious as liver disease. A variety of other conditions may trigger itching in active people, including eczema, heat rash, Grover's disease, sunburn, cholinergic urticaria, exercise-induced anaphylaxis, contact and systemic allergic reactions, infections, parasites, and several systemic diseases. Most of these conditions can be effectively managed with treatments that range from avoidance of environmental irritants to the use of topical agents, antihistamines, systemic corticosteroids, or antibiotics.
Athletes and other active people tend to place great demands on their skin and consequently may develop a variety of skin problems, many of which lead to pruritus. Generalized itching, the most common symptom in dermatology, is an unpleasant, often maddening sensation for patients. Since pruritus may be caused by a particular skin disease or may occur without evidence of any specific skin disorder, diagnosis and therapy can be difficult. An understanding of the wide-ranging causes of pruritus can suggest effective therapies and behavioral changes that will relieve patients' discomfort.
The most common cause of itching, even among young and active people, is xerosis, or dry skin, which can progress to round, red, scaly patches of nummular eczema (figure 1) (1). Two typical symptoms of xerosis are increased itch while undressing at bedtime and less itch in skin-fold and moist areas, such as the axilla and groin.
If a patient has dry skin, a physician should ask about bathing habits; bathing removes natural oils, and excessive bathing, more than once a day for most people, can lead to dry skin. Bathing even once a day may prove excessive if a person scrubs harshly, uses bubble baths, or takes long, hot baths or showers. Use of hot tubs and whirlpools can also quickly lead to xerosis.
Patients with dry skin should take only one short, lukewarm shower a day, use only mild, unscented soaps, and rinse completely. Moisturizers—preferably light, noncomedogenic, and unscented—should be applied after each washing while the skin is still moist. Patches of eczema should be treated with a moderately potent topical corticosteroid such as triamcinolone (2).
Heat is another common physical cause of itchy skin. Heat-related skin conditions include heat rashes, such as the miliarias, and Grover's disease (transient acantholytic dermatosis). Miliaria rubra, or prickly heat (figure 2), is a disease of the sweat glands, and heat sufficient to cause sweating may precipitate this condition. Prickly heat consists of extremely pruritic papulovesicles that are initially discrete but quickly become confluent, especially in skin-fold or sweaty areas. The rash usually subsides if a person avoids sweating for 1 or 2 days. Taking cool baths and applying topical antipruritics such as pramoxine and calamine lotion can also bring relief.
Grover's disease (figure 3) is usually associated with prolonged heat exposure in nonacclimated individuals over 50 years old. Its discrete, red papulovesicles on the torso may resemble an ordinary heat rash, cutaneous candidiasis, or even folliculitis, but the histologic picture is distinct, localized acantholysis in the epidermis. The condition is called transient but frequently persists for months and can be difficult to treat. Topical corticosteroids are often beneficial, but the condition can persist. When routine therapy fails, dermatologic referral or biopsy should be considered.
Heat and perspiration can also cause flare-ups of pre-existing atopic dermatitis. Preventive measures include wearing lightweight clothing and using mild soaps and moisturizers. Recalcitrant cases may require treatment with topical corticosteroids and evaluation for secondary infections.
Outdoor exercise can involve overexposure to sunlight, resulting in sunburns that are painful in their acute stages and itchy as they resolve. The best treatment is to avoid the excessive ultraviolet exposure that comes with being active on or near water, at high altitudes, or between 10 AM and 3 PM. If exposure cannot be avoided, the risk of sunburn can be minimized by applying a sunscreen with a sun protection factor of 15 or higher 20 to 30 minutes before going outside. Active people especially should use a rubproof, waterproof sunscreen that they reapply after sweating or swimming, even on cloudy days or when they are in the shade.
When this advice is too late, sunburn sufferers can obtain some relief by using prostaglandin inhibitors such as ibuprofen, taking cool baths, and applying topical corticosteroids. Moisturizers can relieve itching when the skin peels.
Urticaria and Anaphylaxis
Two less common pruritic conditions fall into the category of allergic reactions to exercise: cholinergic urticaria and exercise-induced anaphylaxis (3). Cholinergic urticaria can develop when the core body temperature increases during exercise; it involves large numbers of 1- to 2-mm wheals that appear 2 to 30 minutes after beginning strenuous exercise. The wheals usually disappear spontaneously 20 to 90 minutes after stopping exercise, and the reaction rarely progresses to respiratory symptoms.
Exercise-induced anaphylaxis causes 10- to 25-mm wheals and intense itch within 5 minutes of beginning exercise. Attacks last from 30 minutes to 4 hours and are frequently associated with flushing, abdominal cramps, diarrhea, and headache. The attacks can progress to angioedema, respiratory distress, and hypotension. A person who has an attack should stop exercise immediately, rest in a cool place, and take a 50-mg dose of oral diphenhydramine. If symptoms progress, he or she will need to use injectible epinephrine from a prepared anaphylaxis package like those used by individuals with insect-sting allergies. People with this condition should carry the injectible epinephrine and never exercise alone.
Outdoor exercise may expose people to plants, which are among the most common causes of contact allergies. But nonplant substances also sometimes cause contact allergies. These allergies produce localized, red, urticarial-to-vesicular lesions whose cause is frequently suggested by the patient's history and the distribution of lesions on the body.
Patients with suspected contact allergies should be asked about contact with plants. Among the most common precipitants are the resins of poison ivy, poison oak, and poison sumac, which cause rhus dermatitis (figure 4). Their resins remain allergenic and, since they do not evaporate, may cling to clothing, sporting equipment, and pets for months. Even in the winter the stem and dead leaves may carry the resins. Contact with these resins results in a rash that most commonly appears on exposed skin as linear streaks with vesicles. The blister fluid does not contain the resin and does not spread the condition. Unfortunately, repeated contacts do not confer immunity, and no consistently reliable desensitization protocol has been developed.
Avoiding the plants and areas where they grow is the best prevention, but, if this is not possible, several new, over-the-counter creams provide an effective barrier to the resins (4). If contact is suspected, the people, pets, and equipment involved should be carefully washed with soap within 10 minutes of exposure, if possible. Should a rash develop, it can be treated with cool compresses and, if relatively localized, high-potency topical corticosteroids. Occasionally, severe or widespread cases need systemic corticosteroid therapy that requires longer, tapering courses, such as prednisone, 60 mg for 5 days, decreasing to 40 mg and 20 mg for 5 days each.
Patients suspected of having contact allergies should also be questioned about balms, adhesives (especially rubber-based glues and tincture of benzoin), and allergy to rubber or metal (especially nickel). Diagnosis may be aided by noticing whether the rash corresponds to the shape of clothing or jewelry or the site of application of topical agents. Patients should also be asked about their use of fragrances, which are the most common allergens in cosmetics, soaps, shampoos, and laundry products. Patients who have cases that are difficult to treat or frequently recurrent should be patch tested.
Systemic Allergic Reactions
Like contact allergies, systemic allergic reactions require careful history-taking and detective work, because identification of the allergen remains the most important part of treatment. Besides being subject to the same food and food-additive allergies that beset the general population, athletes tend to use vitamins, food supplements, and other reputed performance enhancers that are potential allergens. A thorough history should include specific questions about the use of these and other over-the-counter products. Airborne allergens also complicate the picture. Difficult cases may require allergy testing.
Treatment starts with nonsedating antihistamines. Several of the newer products, like fexofenadine and loratidine, minimize drug interactions. More severe cases may require other medications such as doxepin, a potent antihistamine that may cause marked sedation (starting with doses of 10 to 25 mg every 6 hours, as tolerated), or even systemic corticosteroids.
Bacterial or fungal infections can cause pustules on or within the skin or in adnexal structures, such as hair follicles (figure 5). While most infections tend to be painful, superficial infections in athletes may be itchy. Most cases are gram-positive infections with staphylococci or streptococci. Hot tubs or whirlpools that are difficult to keep adequately chlorinated may harbor Pseudomonas; most Pseudomonas infections are self-limiting and need no treatment, other than regulating pool chlorination. Bacterial culture may be helpful in determining the cause of infection; cultures that show no growth or normal flora may be Pityrosporum, a yeast organism that is difficult to culture. Pityrosporum infections respond to oral imidazole antifungal therapy, such as ketoconazole (200 mg daily for 2 weeks) or itraconazole (100 mg twice daily for 2 weeks). Other bacterial infections that itch in their early stages include impetigo, often an infection with both Streptococcus and Staphylococcus organisms.
Tinea versicolor, which may be associated with Pityrosporum infection, can appear as widespread, scaly dermatitis that is usually markedly positive on KOH wet mount and frequently positive with yellowish fluorescence on Wood's (black) light exam. This condition can be treated with topical selenium sulfide shampoo (daily for 1 week) or imidazole antifungal agents, either topical (2% ketaconazole cream for 1 to 2 weeks) or oral (100 mg ketaconazole daily for 3 to 4 days).
Jock itch and tinea pedis (figure 6), probably the most common infection of the skin in athletes, are usually clinically identifiable but may be caused by either candida or true filamentous fungi. Both can be treated with topical imidazoles (once or twice daily for 14 days), and drying powders act prophylactically (1). If imidazoles cannot be used or application does not resolve the infection, a culture is advisable.
Generalized pruritus can be caused by dermatologic conditions like pityriasis rosea and nonspecific viral exanthems. Pityriasis rosea (figure 7), whose cause is unknown, starts as a single, scaly patch (herald patch) and progresses to a rash consisting of scaly, oval lesions that tend to spread for several weeks over the torso, upper arms, and legs but spare the head, palms, and soles; the lesions clear spontaneously in 4 to 6 weeks. Nonspecific viral exanthems, which last days to weeks, frequently are widespread, maculopapular eruptions heralded by or associated with constitutional viral symptoms. Though both conditions tend to be self-limiting, they can be treated with antihistamines and topical antipruritics such as pramoxine or menthol and phenol moisturizers until symptoms abate.
When active people complain of pruritus, physicians should also consider parasites such as scabies, pinworms, and lice and should check for signs on physical examination. Scabies, appearing as small burrows and tiny vesicles, tends to involve body folds with a predilection for finger webs, elbows, periumbilical skin, and genitalia. Pinworms tend to be perirectal and genital and are marked by intense perirectal itching, especially at night. If infestation is suspected, a smear or clear tape epidermal lift should be taken and examined microscopically for ova. Treatment is with pyrvinium pamoate as a single dose of 5 mg/kg of body weight, not to exceed 250 mg, repeated in 1 week.
With the sharing of clothing and athletic equipment, like bicycle helmets, or when hygiene may be a problem, such as on camping or hiking trips, lice are always a consideration. Organism location and examination will indicate the type of infestation. Head lice live in the hair of the scalp and cause itching when they bite the skin of the scalp and neck. Egg sacs, or nits, can be found adhering firmly to the hair shafts. Body lice, 2 to 4 mm long, are clearly visible, live in the folds of clothing, and tend to bite in areas of close contact with clothing. Pubic lice (crab lice, 1 to 2 mm long) are seen in the pubic area and lower abdomen but can be found on the chest or axillary hair. The signs and symptoms of lice are those of insect bites and their associated excoriations. Treatment of head and pubic lice is with gamma benzene shampoo, cream, or lotion; retreatment should occur 4 to 7 days after the initial treatment. Body lice treatment also requires the boiling and ironing of clothing.
Perhaps the most difficult cases to evaluate and treat are generalized pruritus and excoriations without a specific history or primary lesion. Before diagnosing such cases as dry skin or dismissing them as psychogenic, the possibility of systemic disease must be considered (2). The prevalence of pruritus in systemic disorders ranges from quite high in renal disease and liver stasis to less frequent in thyroid disease and as low as 3% in both types of diabetes. Occult malignancies, especially of the lymphoreticular types, and polycythemia vera and iron-deficiency anemia are also associated with pruritus. Evaluation of these diseases is complex (figure 8: not shown) and can require a number of tests. In addition, athletes should be questioned about anabolic steroid use and considered for liver disease if use is suspected.
While finding and correcting the underlying disease is of paramount importance, several modalities can relieve the itch that patients suffer. Treatment with ultraviolet (UV) light has proved beneficial. Both UVB used alone and UVA used with oral psoralens have been very helpful, particularly in treating pruritus from renal disease and liver cholestasis. Although bile acids are believed to be the offending agent in liver disease, bile salt binding agents such as cholestyramine have been consistently helpful in reducing pruritus (2).
Agents that may help relieve nonspecific pruritus include topical doxepin, although cost and systemic absorption limit its widespread use. Other agents that may be useful include oral antihistamines, cyproheptidine (a serotonin and histamine antagonist); oral doxepin; topical and, in extreme cases, systemic corticosteroids; menthol and phenol in lotion form; and topical anesthetics like pramoxine.
Treatment of pruritus in athletes and active patients can be challenging, because they often continue activities that may contribute to the condition. In all cases, a complete history, physical examination, and appropriate laboratory testing are essential for effective treatment. Dermatologic referral should be considered when patients have a visible rash or before doing extensive or expensive testing.
Dr Leshaw is a clinical professor of medicine in the division of dermatology and Dr Scheinberg a clinical professor in the department of medicine at the University of California, San Diego. Drs Leshaw and Scheinberg are in private practice with the Dermatolgist Medical Group of North County, Inc, in Oceanside, Encinitas, and La Jolla, California. Address correspondence to Steven M. Leshaw, MD, 3998 Vista Way, Oceanside, CA 92056.
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