Tinea capitis
Encyclopedia
Tinea capitis is a superficial fungal
infection
(dermatophytosis
) of the scalp
. The disease is primarily caused by dermatophytes in the Trichophyton
and Microsporum
genera that invade the hair shaft. The clinical presentation is typically a single or multiple patches of hair loss, sometimes with a 'black dot' pattern (often with broken-off hairs), that may be accompanied by inflammation, scaling, pustules, and itching. Uncommon in adults, tinea capitis is predominantly seen in pre-pubertal
children, more often in boys than girls.
At least eight species of dermatophytes are commonly associated with tinea capitis. Cases of Trichophyton infection predominate from Central America to the United States and in parts of Western Europe. Infections due to Microsporum species are mainly seen in South America, Southern and Central Europe, Africa and the Middle East. The disease is infectious and can be transmitted by humans, animals, or objects that harbor the fungus. Carrier states also exist where the fungus is present on the scalp but there are no clinical signs or symptoms. Treatment of tinea capitis requires an oral antifungal agent; griseofulvin
is the most commonly used drug, but other newer antimycotic drugs, such as terbinafine
, itraconazole
, and fluconazole
have started to gain acceptance.
, and bald patches where the fungus has rooted itself in the skin. It often presents identically to dandruff or seborrheic dermatitis. The highest incidence in the United States of America is in African American boys of school age.
There are three type of tinea capitis, microsporosis, trichophytosis, and favus
; these are based on the causative microorganism, and the nature of the symptoms. In microsporosis, the lesion is a small red papule
around a hair shaft that later becomes scaly; eventually the hairs break off 1–3 mm above the scalp. This disease used to be caused primarily by Microsporum audouinii, but in Europe, M. canis is more frequently the causative fungus. The source of this fungus is typically sick cats and kittens; it may be spread through person to person contact, or by sharing contaminated brushes and combs. In the United States, Trichophytosis is usually caused by Trichophyton tonsurans, while T. violaceum is more common in Eastern Europe, Africa, and India. This fungus causes dry, non-inflammatory patches that tend to be angular in shape. When the hairs break off at the opening of the follicle
, black dots remain. Favus is caused by T. schoenlenii, and is endemic in South Africa and the Middle East. It is characterized by a number of yellowish, circular, cup-shaped crusts (scutula
) grouped in patches like a piece of honeycomb, each about the size of a split pea, with a hair projecting in the center. These increase in size and become crusted over, so that the characteristic lesion can only be seen around the edge of the scab.
and seborrhoeic dermatitis
; the basis for the diagnosis is positive microscopic examination and microbial culture of epilated hairs. Wood's lamp examination will reveal bright green to yellow-green fluorescence of hairs infected by M. canis, M. audouinii, M. rivalieri, and M. ferrugineum and a dull green or blue-white color of hairs infected by T. schoenleinii. Individuals with M. canis infection trichoscopy
will show characteristic small comma hairs. Histopathology of scalp biopsy shows fungi sparsely distributed in the stratum corneum and hyphae extending down the hair follicle, placed on the surface of the hair shaft. These findings are occasionally associated with inflammatory tissue reaction in the local tissue.
, a secondary metabolite of the fungus Penicillium griseofulvin. This compound is fungistatic (inhibiting the growth or reproduction of fungi) and works by affecting the microtubular system of fungi, interfering with the mitotic spindle
and cytoplasmic microtubules. The recommended pediatric dosage is 10 mg/kg/day for 6–8 weeks, although this may be increased to 20 mg/kg/d for those infected by T. tonsurans, or those who fail to respond to the initial 6 weeks of treatment. Unlike other fungal skin infections that may be treated with topical
therapies like creams applied directly to the afflicted area, griseofulvin must be taken orally to be effective; this allows the drug to penetrate the hair shaft where the fungus lives. The effective therapy rate of this treatment is generally high, in the range of 88–100%.
Other oral antifungal treatments for tinea capitis also frequently reported in the literature include terbinafine
, itraconazole
, and fluconazole
; these drugs have the advantage of shorter treatment durations than griseofulvin. However, concern has been raised about the possibility of rare side effects like liver toxicity
or interactions with other drugs; furthermore, the newer drug treatments tend to be more expensive than griseofulvin.
On September 28, 2007, the U.S. Food and Drug Administration
stated that Lamisil (Terbinafine
hydrochloride, by Novartis AG) is a new treatment
approved for use by children aged 4 years and older. The antifungal granules can be sprinkled on a child's food to treat the infection. Lamisil carries hepatotoxic risk, and can cause a metallic taste in the mouth.
and Trichophyton
is a contagious disease that is endemic in many countries. Afflicting primarily pre-pubertal
children between 6 and 10 years, it is more common in males than females; rarely does the disease persist past age sixteen. Because spread is thought to occur through direct contact with afflicted individuals, large outbreaks have been known to occur in schools and other places where children are in close quarters; however, indirect spread through contamination with infected objects (fomites) may also be a factor in the spread of infection. In the USA, tinea capitis is thought to occur in 3-8% of the pediatric population; up to one-third of households with contact with an infected person may harbor the disease without showing any symptoms.
The fungal species responsible for causing tinea capitis vary according to the geographical region, and may also change over time. For example, Microsporum audouinii
was the predominant etiological agent in North America and Europe until the 1950s, but now Trichophyton tonsurans
is more common in the USA, and becoming more common in Europe and the United Kingdom. This shift is thought to be due to the widespread use of griseofulvin, which is more effective against M. audounii than T. tonsurans; also, changes in immigration patterns and increases in international travel have likely spread T. tonsurans to new areas. Another fungal species that has increased in prevalence is Trichophyton violaceum, especially in urban populations of the United Kingdom and Europe; this fungus seems to especially target black children, although children from all ethnic backgrounds are susceptible.
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
infection
Mycosis
A mycosis is a fungal infection of animals, including humans. Mycoses are common, and a variety of environmental and physiological conditions can contribute to the development of fungal diseases...
(dermatophytosis
Dermatophytosis
Dermatophytosis or ringworm is a clinical condition caused by fungal infection of the skin in humans, pets such as cats, and domesticated animals such as sheep and cattle. The term "ringworm" is a misnomer, since the condition is caused by fungi of several different species and not by parasitic worms...
) of the scalp
Scalp
The scalp is the anatomical area bordered by the face anteriorly and the neck to the sides and posteriorly.-Layers:It is usually described as having five layers, which can conveniently be remembered as a mnemonic:...
. The disease is primarily caused by dermatophytes in the Trichophyton
Trichophyton
The fungus genus Trichophyton is characterized by the development of both smooth-walled macro- and microconidia. Macroconidia are mostly borne laterally directly on the hyphae or on short pedicels, and are thin- or thick-walled, clavate to fusiform, and range from 4 to 8 by 8 to 50 um in size....
and Microsporum
Microsporum
Microsporum is a genus of fungi that causes tinea capitis, tinea corpus, ringworm, and other dermatophytoses. Microsporum forms both macroconidia and microconidia on short conidiophores...
genera that invade the hair shaft. The clinical presentation is typically a single or multiple patches of hair loss, sometimes with a 'black dot' pattern (often with broken-off hairs), that may be accompanied by inflammation, scaling, pustules, and itching. Uncommon in adults, tinea capitis is predominantly seen in pre-pubertal
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
children, more often in boys than girls.
At least eight species of dermatophytes are commonly associated with tinea capitis. Cases of Trichophyton infection predominate from Central America to the United States and in parts of Western Europe. Infections due to Microsporum species are mainly seen in South America, Southern and Central Europe, Africa and the Middle East. The disease is infectious and can be transmitted by humans, animals, or objects that harbor the fungus. Carrier states also exist where the fungus is present on the scalp but there are no clinical signs or symptoms. Treatment of tinea capitis requires an oral antifungal agent; griseofulvin
Griseofulvin
Griseofulvin is an antifungal drug that is administered orally. It is used both in animals and in humans, to treat fungal infections of the skin and nails...
is the most commonly used drug, but other newer antimycotic drugs, such as terbinafine
Terbinafine
Terbinafine hydrochloride is a...
, itraconazole
Itraconazole
Itraconazole , invented in 1984, is a triazole antifungal agent that is prescribed to patients with fungal infections. The drug may be given orally or intravenously.-Medical uses:...
, and fluconazole
Fluconazole
Fluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. In a bulk powder form, it appears as a white crystalline powder, and it is very slightly soluble in water and soluble in alcohol. It is commonly marketed under the trade...
have started to gain acceptance.
Symptoms
It may appear as thickened, scaly, and sometimes boggy swellings, or as expanding raised red rings (ringworm). Common symptoms are severe itching of the scalp, dandruffDandruff
Dandruff is the shedding of dead skin cells from the scalp . Dandruff is sometimes caused by frequent exposure to extreme heat and cold. As it is normal for skin cells to die and flake off, a small amount of flaking is normal and common; about 487,000 cells/cm2 get released normally after...
, and bald patches where the fungus has rooted itself in the skin. It often presents identically to dandruff or seborrheic dermatitis. The highest incidence in the United States of America is in African American boys of school age.
There are three type of tinea capitis, microsporosis, trichophytosis, and favus
Favus
Favus is a disease usually affecting the scalp, but occurring occasionally on any part of the skin, and even at times on mucous membranes.-Presentation:...
; these are based on the causative microorganism, and the nature of the symptoms. In microsporosis, the lesion is a small red papule
Papule
A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in size from a pinhead to 1 cm.With regard to the quote "...varying in size from a pinhead to 1cm," depending on which text is referenced, some authors state the cutoff between a papule and a plaque as 0.5cm,...
around a hair shaft that later becomes scaly; eventually the hairs break off 1–3 mm above the scalp. This disease used to be caused primarily by Microsporum audouinii, but in Europe, M. canis is more frequently the causative fungus. The source of this fungus is typically sick cats and kittens; it may be spread through person to person contact, or by sharing contaminated brushes and combs. In the United States, Trichophytosis is usually caused by Trichophyton tonsurans, while T. violaceum is more common in Eastern Europe, Africa, and India. This fungus causes dry, non-inflammatory patches that tend to be angular in shape. When the hairs break off at the opening of the follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
, black dots remain. Favus is caused by T. schoenlenii, and is endemic in South Africa and the Middle East. It is characterized by a number of yellowish, circular, cup-shaped crusts (scutula
Scutula
Scutula is a genus of lichenized fungi in the family Pilocarpaceae.-External links:*...
) grouped in patches like a piece of honeycomb, each about the size of a split pea, with a hair projecting in the center. These increase in size and become crusted over, so that the characteristic lesion can only be seen around the edge of the scab.
Diagnosis
Tiniea capitis may be difficult to distinguish from other skin diseases that cause scaling, such as psoriasisPsoriasis
Psoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of...
and seborrhoeic dermatitis
Seborrhoeic dermatitis
Seborrhoeic dermatitis is an inflammatory skin disorder affecting the scalp, face, and torso. Typically, seborrheic dermatitis presents with scaly, flaky, itchy, and red skin. It particularly affects the sebaceous-gland-rich areas of skin...
; the basis for the diagnosis is positive microscopic examination and microbial culture of epilated hairs. Wood's lamp examination will reveal bright green to yellow-green fluorescence of hairs infected by M. canis, M. audouinii, M. rivalieri, and M. ferrugineum and a dull green or blue-white color of hairs infected by T. schoenleinii. Individuals with M. canis infection trichoscopy
Trichoscopy
Trichoscopy is a method of hair and scalp evaluation and is used for diagnosing hair and scalp diseases. The method is based on dermoscopy and videodermoscopy. In trichoscopy hair and scalp structures may be visualized at many-fold magnification...
will show characteristic small comma hairs. Histopathology of scalp biopsy shows fungi sparsely distributed in the stratum corneum and hyphae extending down the hair follicle, placed on the surface of the hair shaft. These findings are occasionally associated with inflammatory tissue reaction in the local tissue.
Treatment
The treatment of choice by dermatologists is a safe and inexpensive oral medication, griseofulvinGriseofulvin
Griseofulvin is an antifungal drug that is administered orally. It is used both in animals and in humans, to treat fungal infections of the skin and nails...
, a secondary metabolite of the fungus Penicillium griseofulvin. This compound is fungistatic (inhibiting the growth or reproduction of fungi) and works by affecting the microtubular system of fungi, interfering with the mitotic spindle
Mitotic spindle
In cell biology, the spindle fibers are the structure that separates the chromosomes into the daughter cells during cell division. It is part of the cytoskeleton in eukaryotic cells...
and cytoplasmic microtubules. The recommended pediatric dosage is 10 mg/kg/day for 6–8 weeks, although this may be increased to 20 mg/kg/d for those infected by T. tonsurans, or those who fail to respond to the initial 6 weeks of treatment. Unlike other fungal skin infections that may be treated with topical
Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
therapies like creams applied directly to the afflicted area, griseofulvin must be taken orally to be effective; this allows the drug to penetrate the hair shaft where the fungus lives. The effective therapy rate of this treatment is generally high, in the range of 88–100%.
Other oral antifungal treatments for tinea capitis also frequently reported in the literature include terbinafine
Terbinafine
Terbinafine hydrochloride is a...
, itraconazole
Itraconazole
Itraconazole , invented in 1984, is a triazole antifungal agent that is prescribed to patients with fungal infections. The drug may be given orally or intravenously.-Medical uses:...
, and fluconazole
Fluconazole
Fluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. In a bulk powder form, it appears as a white crystalline powder, and it is very slightly soluble in water and soluble in alcohol. It is commonly marketed under the trade...
; these drugs have the advantage of shorter treatment durations than griseofulvin. However, concern has been raised about the possibility of rare side effects like liver toxicity
Hepatotoxicity
Hepatotoxicity implies chemical-driven liver damage.The liver plays a central role in transforming and clearing chemicals and is susceptible to the toxicity from these agents. Certain medicinal agents, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure...
or interactions with other drugs; furthermore, the newer drug treatments tend to be more expensive than griseofulvin.
On September 28, 2007, the U.S. Food and Drug Administration
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
stated that Lamisil (Terbinafine
Terbinafine
Terbinafine hydrochloride is a...
hydrochloride, by Novartis AG) is a new treatment
Therapy
This is a list of types of therapy .* Adventure therapy* Animal-assisted therapy* Aquatic therapy* Aromatherapy* Art and dementia* Art therapy* Authentic Movement* Behavioral therapy* Bibliotherapy* Buteyko Method* Chemotherapy...
approved for use by children aged 4 years and older. The antifungal granules can be sprinkled on a child's food to treat the infection. Lamisil carries hepatotoxic risk, and can cause a metallic taste in the mouth.
Epidemiology
Tinea capitis caused by species of MicrosporumMicrosporum
Microsporum is a genus of fungi that causes tinea capitis, tinea corpus, ringworm, and other dermatophytoses. Microsporum forms both macroconidia and microconidia on short conidiophores...
and Trichophyton
Trichophyton
The fungus genus Trichophyton is characterized by the development of both smooth-walled macro- and microconidia. Macroconidia are mostly borne laterally directly on the hyphae or on short pedicels, and are thin- or thick-walled, clavate to fusiform, and range from 4 to 8 by 8 to 50 um in size....
is a contagious disease that is endemic in many countries. Afflicting primarily pre-pubertal
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
children between 6 and 10 years, it is more common in males than females; rarely does the disease persist past age sixteen. Because spread is thought to occur through direct contact with afflicted individuals, large outbreaks have been known to occur in schools and other places where children are in close quarters; however, indirect spread through contamination with infected objects (fomites) may also be a factor in the spread of infection. In the USA, tinea capitis is thought to occur in 3-8% of the pediatric population; up to one-third of households with contact with an infected person may harbor the disease without showing any symptoms.
The fungal species responsible for causing tinea capitis vary according to the geographical region, and may also change over time. For example, Microsporum audouinii
Microsporum audouinii
Microsporum audouinii is a species of fungus in the genus Microsporum.It is associated with the disease known as tinea, an infection of keratinized tissues like epidermis, hair and nails...
was the predominant etiological agent in North America and Europe until the 1950s, but now Trichophyton tonsurans
Trichophyton tonsurans
Trichophyton tonsurans is a species of fungus in the Arthrodermataceae family. It is a common cause of tinea capitis in the United Kingdom....
is more common in the USA, and becoming more common in Europe and the United Kingdom. This shift is thought to be due to the widespread use of griseofulvin, which is more effective against M. audounii than T. tonsurans; also, changes in immigration patterns and increases in international travel have likely spread T. tonsurans to new areas. Another fungal species that has increased in prevalence is Trichophyton violaceum, especially in urban populations of the United Kingdom and Europe; this fungus seems to especially target black children, although children from all ethnic backgrounds are susceptible.