Section 6. Fungal Infections

Fungal infections of the scalp are extremely common in children. The diagnosis of tinea capitis should be entertained in any child in whom patches of incomplete alopecia, crusting, or scaling are found in the scalp. In previous decades, Microsporum canis and M. audouinii were the most common pathogenic fungi infecting the scalp. The latter frequently causes a discrete grayish patch of hair loss (Fig. 6-1). In most parts of the United States and in many other parts of the world, Trichophyton tonsurans is now the predominant organism causing tinea capitis. In the United States, this form of tinea capitis is seen almost exclusively in African American children. In some children, this dermatophyte causes discrete and dramatic areas of hair loss studded by the stubs of broken hairs, the so-called black-dot ringworm (Fig. 6-2). In others, there are only small and unimpressive patches of “seborrheic” scale with minimal hair loss or groups of small pustules.

Because T. tonsurans does not fluoresce, the Wood's light is no longer of use in most cases. However, diagnosis can be confirmed by the use of either potassium hydroxide preparation or fungal culture. Pictured here is an inflammatory response to infection with T. tonsurans. Children whose scalps are infected with this dermatophyte may also develop regional lymphadenopathy (Fig. 6-4), or a fine papular eruption that spreads from the face and neck to other skin surfaces (an id reaction). Attempts to treat tinea capitis with topical antifungal agents alone are doomed to failure. Oral griseofulvin is the most effective form of therapy. The use of selenium sulfide shampoo may be effective in preventing spread to classmates and siblings.

In some children, an exuberant inflammatory response to the infecting dermatophyte may occur. This boggy and tender mass is termed a kerion, a word that in Greek means a honeycomb, honey, or beeswax and is intended to describe the clinical appearance. Children with a kerion may also develop localized lymphadenopathy and fever. Although bacterial superinfection may sometimes occur, misdiagnosis of a kerion as a bacterial infection of the scalp is an all too common pitfall. The proper treatment is oral griseofulvin. In some cases, a brief course of oral prednisone may minimize scarring.

Before treatment or shortly after starting griseofulvin for tinea capitis, some patients develop a pruritic eruption that is a hypersensitivity reaction. These patients develop erythematous papules, papulovesicles, and sometimes oval plaques concentrated on the face, neck, trunk, and upper extremities. There is no need to discontinue the griseofulvin, for the eruption resolves in 1–2 weeks. Relief can be obtained with the application of low-potency topical corticosteroids. It is important to differentiate this from a true drug eruption.

Superficial fungal infections of the skin are among the most common of all pediatric dermatoses. Infection at the sites pictured here may also be termed tinea faciei. Note the ring shape of the active periphery of the lesions in the infant in Fig. 6-7 and the more inflammatory process in the patient in Figs. 6-8 and 6-9.

T. tonsurans, T. rubrum, and T. mentagrophytes are common pathogens. Cutaneous infection with zoophilic species, such as M. canis, usually results from close contact with a household pet. On the body, fungi lodge in the stratum corneum and do not invade lanugo hairs.

Therefore, topically applied antifungal agents, such as the azole and allylamine agents, are effective therapies. Occasionally, a cutaneous fungal infection, particularly on the face, is misdiagnosed as atopic or contact dermatitis. The application of topical steroids to such a lesion will often cause dramatic worsening of the condition as shown in this figure.

The illustrations are of more superficial fungal infection of relatively hairless skin. The annular lesions in Figs. 6-10 and 6-11 resulted from infection with T. tonsurans. Note the ring in ring morphology in Fig. 6-11. The numerous scaly rings in Fig. 6-12 are due to M. canis. In the cases illustrated, clinical diagnosis of a superficial fungal infection is reasonably certain, and one may guess that the causative fungus is a microsporum or trichophyton. A potassium hydroxide preparation of a scale obtained from the edge of a lesion will identify the hyphae.

Definitive diagnosis depends on mycologic culture of the scale from a lesion. In cases of candidiasis, favus, and tinea imbricata (see Fig. 6-31), the causative organism can frequently and confidently be guessed correctly. In general, one may say that M. canis, M. audouinii, T. tonsurans, and T. schoenleinii can infect scalp and hairless skin, and T. rubrum and Candida albicans can infect hairless skin and nails.

Illustrated here is superficial fungal infection of glabrous skin caused by Microsporum gypseum. The clinical appearance is somewhat different from that of the condition caused by other dermatophytes in that, though a round lesion, it is not a ring of active periphery around a relatively healed center. Still, the superficiality, the scaling, and the low-grade inflammatory reaction are typical of a fungal infection. It can be proved by culture of the causative fungus.

Tinea corporis can occur in very young children, and is sometimes misdiagnosed because the primary care provider has not considered that possibility. This infant developed typical arcuate lesions on the face. The child's caretaker had a fungal infection of the hand.

On rare occasions, a marked inflammatory response to the presence of a dermatophyte leads to a vesicular or bullous eruption. The clinical presentation seen in this figure must be differentiated from acute contact dermatitis, bullous impetigo, or an autoimmune blistering disease such as linear IgA dermatosis.

This clinical presentation of tinea occurs when fungal elements penetrate the hair follicle and cause a deeper infection. Typical lesions are eythematous papules and nodules. Most typically, Majocchi's granuloma occurs on the legs of adolescent girls and is spread by shaving. In this case, the patient was applying a topical corticosteroid to undiagnosed tinea and this caused worsening.

The groin is a common site of acute and then enduring superficial fungal infection. Epidermophyton floccosum, T. rubrum, and C. albicans are the commonest infecting fungi. In infants, C. albicans is the usual pathogen; in older children and adults, all are common. Intertriginous spaces, such as groin, axillae, and digital webs, are particularly susceptible to fungal infection because the pH of these areas is less acid than elsewhere, temperature is higher, and humidity is greater.

Superficial fungal infection of the feet is somewhat unique because of the location. Between the toes (most commonly the fourth and fifth), the condition appears as erythema, maceration, and scaling. In some cases, this may become secondarily infected (Fig. 6-19). It is attended by itching or vague discomfort. On the sole and the lateral aspects of the feet, scattered pustules and vesicles with surrounding erythema and edema may occur. More commonly, there is persistent dry scale in a “moccasin” distribution with minimal inflammation.

The fungi that are commonly found are E. floccosum, T. mentagrophytes, T. rubrum, and C. albicans. Fungal infections of the feet, although rare in infants and young children, must be considered when presented with erythema and scaling of the feet. More likely diagnoses with this presentation are juvenile plantar dermatosis and contact dermatitis.

Sweating, friction, and debris promote fungal infection. During early adolescence, there is a marked increase in the incidence of tinea pedis. For most patients, the use of topical antifungal therapy, along with the wearing of sandals and light cotton socks, is an adequate therapy.

Tinea unguium (fungal infection of the nails) is somewhat uncommon during childhood. After puberty, its frequency increases with age. Usually, onychomycosis is associated with tinea pedis. Fungal culture of the nails is sometimes difficult but extremely important in confirming the diagnosis. Onychomycosis is the most difficult of the superficial fungal infections to treat because the nail plate is not penetrated by (most) topically applied agents. Systemic antifungal agents such as itraconazole and terbinafine appear effective in the treatment of onychomycosis. The illustrations show infection with dermatophytes. Note the distortion of nail plates in Fig. 6-22 and the onycholysis (separation of nail plates from nail beds) in Fig. 6-23. Infection by dermatophytes usually proceeds in a distal-to-proximal direction. Infection of nails by C. albicans is different in that it is more acute (frequently purulent) and tends first to involve the lateral and proximal nail folds.

Superficial fungal infection of the palms usually presents with erythema and whitish scale, predominantly in the palmar creases. It is almost always associated with tinea pedis. Generally tinea manuum involves one hand, but when both hands are involved, it is not symmetrical. The causative organism is usually T. rubrum. The condition may be treated with either topical imidazole creams or with oral antifungals. On the dorsa of the hands, the infecting fungi are more likely to be those that cause tinea corporis elsewhere.

Fungal infections are sometimes accompanied by cutaneous eruptions that are the result of sensitization to the products of the fungi. Such cutaneous effects are called dermatophytids and are sterile of the fungi. Dermatophytids are papular and vesicular lesions, commonly on the hands. They usually stem from fungal infections of the foot that have become inflamed or irritated. The palmar blisters in this figure are the result of such an event.

This title designates a superficial fungal infection (tinea) that changes color (versicolor). The causative organism was originally called Malassezia furfur and is now called Pityrosporum orbiculare. Tinea versicolor typically causes numerous patchy scaling macules on the upper chest and back, proximal arms, and neck (Figs. 6-26 and 6-28). Facial involvement may occur (Fig. 6-27). The lesions may be hypopigmented, as illustrated here, or brown-orange, depending on the skin color of the patient and the degree of recent sun exposure. The organism is believed to prevent either the formation of melanin or the transfer of melanosomes into keratinocytes. The formation of azelaic acid is another suggested mechanism for the resultant hypopigmentation. Although tinea versicolor usually makes its appearance after puberty, it can develop in childhood and is occasionally seen in breast-fed infants. Tinea versicolor is usually asymptomatic but may itch slightly. The organism cannot be cultured, but diagnosis is aided by the orange or brown glow of lesional skin under a Wood's light and by the “spaghetti and meatballs” appearance of clustered hyphae and spores on potassium hydroxide preparation.

Illustrated here are small, scaly macules, which are in this case darker than the surrounding skin (Figure 6-29). There are several approaches to the treatment of tinea versicolor. Small areas of involvement can be eradicated by the use of an imidazole cream. In patients with more extensive disease, the best approach is the use of a selenium sulfide or sodium thiosulfate lotion. Patients should be warned that treatment of tinea versicolor does not diminish the very high rate of recurrence and that the return to normal skin color may be delayed for weeks to months after the completion of therapy.

This is an infection of the stratum corneum, commonly on a palm, that is caused by the dematiaceous fungus Exophiala (Cladosporium werneckii). It occurs most commonly in tropical regions. The clinical appearance is a tan-to-black discoloration with sharp borders that enlarge slowly. It can be mistaken for a melanocytic nevus, melanoma, or simple artifact. The correct diagnosis can be confirmed by potassium hydroxide examination or fungal culture. Treatment consists of a keratolytic lotion or topical imidazole cream.

Tinea imbricata is a superficial fungal infection of the glabrous skin that is seen in a number of tropical countries. The causative organism is Trichophyton concentricum. Brown papules evolve into annular plaques. As the infection continues, many concentric ring lesions develop, which resemble the patterning of a tortoise shell. Oral antifungals are effective therapy but relapses occur.

This chronic form of tinea capitis is caused by Trichophyton schoenleinii. It occurs in parts of Europe, Africa, and South America as well as in some rural areas of the United States and Canada. Pictured here are the typical scaly patches seen in favus. The yellowish cup-like crusts, called scutula, are a distinctive part of this disease. The coalescent crusts form a plaque that emits a characteristic mousy odor. This form of fungal infection of the scalp may persist into adult life.

The parti-colored granulomatous process pictured here is of 12 years' duration. It started as a small nodule, developed slowly into a verrucous mass, and acquired satellite extensions. The condition, so reminiscent of a tuberculous process, is a deep fungal infection caused by the species of Phialophora, Fonsecaea, and Cladosporium, which are indigenous to South America and other regions with warm climates. Lesions that are too large for surgical excision are treated with combinations of systemic flucytosine, amphotericin B, and ketoconazole.

This disease, caused by the dimorphic fungus Coccidioides immitis, is endemic to the southwestern United States and parts of Central and South America. Most individuals in those areas develop the disease as an inconsequential upper-respiratory infection. However, severe disseminated disease can follow pulmonary infection and may involve the skin. In this case, the lesions are typically abscesses, nodules, or verrucous and inflammatory plaques. Primary infection of the skin, which is rare, is accompanied by regional lymphadenopathy. Amphotericin B is the customary treatment.

Cutaneous infection with Sporothrix schenckii is a disease with worldwide distribution. The majority of cases are seen in Central and South America but outbreaks occur in the United States. The disease affects both children and adults and occurs when the causative fungus, in either contaminated soil or plant materials, contacts traumatized skin. The thorn of a rose bush may provide both the organism and a site of entry, and there have been outbreaks among children playing among bales of hay. Pictured here is the most common form of sporotrichosis, the lymphocutaneous type. It causes an ulcerated lesion at the site of inoculation (Fig. 6-35) and a string of nodules or ulcerations along the lines of lymphatic drainage (Fig. 6-36).

These tender secondary lesions may become chronic and extend into subcutaneous tissues. Very rarely, and especially in the immunocompromised host, disseminated or systemic sporotrichosis follows cutaneous infection. Diagnosis of sporotrichosis can be confirmed by culture of exudate or tissue from the skin lesions on Sabouraud's agar.

This figure illustrates a somewhat less common form of the disease, fixed cutaneous sporotrichosis. The patient fell on rocks while playing in the country and sustained abrasions on an arm and elbow. Sporothrix schenckii was cultured from the crusted plaques in both locations. In this clinical form, the deep fungal infection remains confined to one area of the skin and has no tendency toward lymphatic spread.

This is an example of fixed cutaneous sporotrichosis on the face. Lesions of this type are usually attributed to exposure during outdoor play. Specifically, acquisition of Sporothrix schenkii has been attributed to playing in bales of hay or in sphagnum moss. Transmission from a cat has also been described.

Cutaneous infection with C. albicans tends to occur in areas that are chronically moist, warm, and macerated. For this reason, Candida is among the most common causes of diaper dermatitis. An early diaper rash in Fig. 6-40 illustrates some of the distinctive features of monilial infection. Note the confluent, glistening, beefy-red erythema, which begins in the perianal skin and spreads by local extension. There are numerous small satellite lesions. If untreated, this rash will go on to involve the gluteal folds, buttocks, and inner thighs. More extensive involvement is seen in Fig. 6-41; note the peripheral scaling and again the satellite lesions. On occasion, these peripheral pustules and papules will involve the entire abdomen and back. Diagnosis of cutaneous candidiasis can be confirmed by potassium hydroxide preparation or by fungal culture. Treatment consists of the use of imidazole creams, such as ketoconazole, or nystatin. The several preparations that also contain a fluorinated topical steroid are not required for this condition and may lead to adverse local side effects.

The angles of the mouth are also the places where intertriginous conditions favor the overgrowth of ubiquitous C. albicans, streptococci, staphylococci, and other ordinarily saprophytic but facultatively pathogenic microorganisms. The condition produced at the angles of the mouth (Fig. 6-42) is called perlèche or angular stomatitis. From such a beginning or even without it, the lips themselves may become involved in the manner pictured in Fig. 6-43. These conditions are not to be confused with vitamin deficiencies, which are often overdiagnosed. Perlèche is more likely to be a mixed infection with C. albicans and bacteria. Therefore, treatment should be with a preparation that contains both an antimonilial agent like nystatin and a topical antibiotic. Candidal cheilitis is more difficult to treat and requires persistent application of a candicidal agent. Candidiasis in children with immunologic deficiency is particularly difficult to treat.

The immunologic inability to handle C. albicans infection results in recurrent and severe infection of the mucous membranes, skin, and nails. Affected children have T-cell deficiencies due to a wide variety of underlying causes but manifest their mucocutaneous disease in similar fashion. Illustrated here are chronic perlèche and candidal cheilitis (Fig. 6-44) and a circumscribed, erythematous, and hyperkeratotic candidal rash in the diaper area (Fig. 6-45). Both areas of involvement in these patients have been resistant to conventional antimonilial therapies. Chronic mucocutaneous candidiasis can also occur as an autosomal recessive syndrome, with no associated abnormalities. Early in their course, these children may be indistinguishable from those with profound immune deficiency disorders such as Swiss-type agammaglobulinemia, DiGeorge's syndrome, and Nezelof's syndrome. An identical clinical picture of unusual and persistent mucocutaneous monilial infection may be the presenting feature of infection with the human immunodeficiency virus.

Chronic mucocutaneous candidiasis may in some patients lead to granuloma formation in the areas of infection. The face is a common site for the formation of these indurated and hyperkeratotic plaques. Note how the lesions on the forehead of the patient in Fig. 6-46 resemble some forms of tuberculosis cutis, sporotrichosis, and chromoblastomycosis, previously pictured and described. Figure 6-47 illustrates typical nail involvement in chronic mucocutaneous candidiasis. Patients develop swelling and tenderness of the proximal and lateral nail folds. Eventually, the nails become brittle and discolored and may be destroyed by the process. Treatment with oral fluconazole is often effective. Some patients with acrodermatitis enteropathica (zinc deficiency) and certain children with iron deficiency develop chronic mucocutaneous candidiasis. Dietary or parenteral replacement of the deficient mineral, as required, leads to resolution of the candidal infections.

In many patients, chronic mucocutaneous candidiasis is a part of an autoimmune syndrome that has profound effects on the endocrine system. Hypoparathyroidism is the most common of these autoimmune syndromes and is present in more than 80 percent of the children with chronic mucocutaneous candidiasis. The sparse, brittle hair (Fig. 6-48) and the deforming effect of chronic hypocalcemia on tooth formation (Fig. 6-49) are both features of hypoparathyroidism. Other endocrine disorders that may be associated with chronic mucocutaneous candidiasis include hypoadrenocorticism, gonadal insufficiency, and thyroid abnormalities. Alopecia areata and vitiligo may also occur in these patients. Children with so-called candidiasis endocrinopathy syndrome have the same nail, skin, and mucous membrane involvement as do children with chronic mucocutaneous candidiasis from other causes. The onset of these manifestations usually occurs in early childhood, and the endocrine disease develops during adolescence.

The presence of a generalized candidal dermatitis at birth is the result of intrauterine infection. Typically, erythematous papulovesicles and macules evolve into pustules and areas of superficial desquamation over a period of 6–8 days. The characteristic lesions frequently involve the palms and soles and may be accompanied by paronychias and true nail involvement. In contrast to neonatal candidiasis (acquired during passage through an infected birth canal), the diaper area and oral mucosa tend to be spared. If congenital candidiasis involves only the skin, the disease follows a benign course. Infants with low birth weight or respiratory distress may develop disseminated infection and require systemic therapy.