Page 183 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 6-8 Infectious Diseases

TINEA CRURIS AND TINEA CAPITIS

DERMATOPHYTOSES (Continued)

general public, because of personal involvement or that
of someone they know. This fungal infection is seen in
two predominant types, the interdigital type and the
moccasin type. The interdigital subtype forms macer-
ated, red patches in the toe web spaces. The areas
can become pruritic and can lead to onychomycosis.
Moccasin-type tinea pedis involves the entire foot and
is the less common of the two types. T. rubrum is the
most frequent isolate in these cases.
Tinea manuum, also most frequently caused by T.
rubrum, predominantly affects one hand only. It is com- Tinea cruris (male), “jock itch,”
monly seen in association with bilateral tinea pedis and Tinea cruris (female) a very common infecton in males
therefore has been called “one hand two feet disease.”
The reason that it affects only one hand is unknown.
The most frequent complaint is itching and the appear-
ance of the red annular patches.
Majocchi’s granuloma is a form of fungal folliculitis
caused by one of the dermatophyte species. It is univer-
sally seen in patients who have been treated with corti-
costeroids for a presumed form of dermatitis. As the
patient continues to apply the steroid cream to the
patch of fungal infection, the redness spreads, and pus-
tules may form within the affected region. The pustules
are based on a hair follicle, and the hair may be absent
or easily pulled from the region with minimal or no
discomfort. Removal of the hair and use of a potassium
hydroxide (KOH) preparation allows the fungus to be
seen. This form of folliculitis must be treated with a
systemic agent, because the topical antifungals do not
penetrate deep enough into the depths of the hair fol-
licle or into the hair shaft, as would be required to treat
an endothrix fungus. Fungal species are designated as
endothrix or ectothrix species based on their ability to
penetrate the hair shaft epithelium.
Tinea capitis is seen almost exclusively in children
and is most commonly caused by T. tonsurans. This
infection begins as a small, pruritic patch in the scalp
that slowly expands outward. Hair loss is prominent
because the fungus invades the hair shaft and can cause
the hair to break. A frequent clinical sign is “black dot”
tinea. This is the clinical finding of tiny, broken-off
hairs that appear as black dots just at the level of the
scalp. Posterior occipital adenopathy is always seen in
cases of tinea capitis, and its absence should make one
reconsider the diagnosis. If a child presents with a scaly
patch in the scalp and associated hair loss, it should be
treated as tinea capitis until proven otherwise. A KOH
examination of the hair or of a scalp scraping often, but
not always, shows evidence of a dermatophyte. A fungal
culture can be used in these cases to confirm the diag-
nosis if the KOH examination is negative. The culture Tinea capitis. Scaly patches with associated alopecia
sample is easily obtained by rubbing the scaly patch
with a toothbrush and collecting the scale that is
removed in a sterile container. The cultures are grown
in the laboratory on dermatophyte test medium (DTM), class. The kerion often appears as a large, inflamed, bacteria, especially Staphylococcus species. Treatment is
and growth is often seen in 2 to 4 weeks. Tinea capitis boggy-feeling plaque with alopecia. Serous drainage based on the use of systemic oral antifungals in associa-
requires at least 6 weeks of systemic oral therapy to and crusting are also present. These plaques are very tion with an oral corticosteroid to decrease the massive
clear, and all the patients’ pets, especially cats, should tender to palpation, and children complain of pain inflammatory response. Any bacterial coinfections
be evaluated by a veterinarian for evidence of disease. even when the lesions are not manipulated. Alopecia must be treated at the same time. Scarring alopecia
A kerion is a boggy plaque found on occasion in tinea overlies the plaque, and if it is severe, a kerion can may be permanent and may lead to morbidity for the
capitis that results from a massive immune inflamma- lead to permanent scarring alopecia. Posterior occipital child.
tory response to the causative fungal agent. The fungi and cervical adenopathy is present and tender to palpa- Tinea unguium, or onychomycosis, is clinically rec-
most likely to cause this reaction are in the zoophilic tion. The kerion often become impetiginized with ognized by thick, dystrophic, crumbling nails. One or

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 169