La red de asentamientos de la Sagra Toledana

ClInICAl FeATUReS

The lesion usually begins as a non­descript, asym p tomatic, indolent papule, which in due course enlarges to form nodules and satellite papules. This is accompanied by a globose swel ling in and around the primary site. At this point, the nodules may soften, and form dis­

char ging sinuses. The suppurative fluid usually displays granules with a hue characteristic of the causative agent. The granules can be reco gnized with the naked eye. The foot and lower leg are commonly affected. After several years, the foot becomes massively enlarged (tumefac tion), with draining sinuses, fibrotic nodules, and irregular contractures (Fig. 16.1). The lesions are usually painless and their evolution, until the grossly deformed limb is formed, is so gradual that the patients seldom report for treatment.

By the time the patient applies for therapy, the disease has usually spread to the underlying bones. This is more so in the infections by S.

somalienses. The lesions do not metastasize, and only spread locally. Other infrequent sites of mycetomas are the hands, shoulders, buttocks, and the head, in that order.

DIAgnOSIS

In the early stages, the ulcers and sinuses of mycetoma may mimic leg ulcers of other infec tive etiology. However, chronicity, asymptoma tic

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Deep Mycotic Infection

nature, and absence of systemic signs easily differentiate them. Ulcers induced by venous stasis and arterial insufficiency are bilateral, where as mycetomas are usually unilateral.

Myce tomas also have to be differentiated from elephantiasis of the foot, skin tuberculosis, chro momycosis, chronic osteomyelitis, and sporotri cho sis.

The diagnosis is usually based on the chro­

nology of the clinical features, demonstration of various colored granules from the discharged pus, and the culture of the causative organism.

It is cultured in Sabourauds’ dextrose agar me­

dium, which takes about 1 to 2 months. Histo­

pathological examination of the tissue section reveals numerous chronic granulomas, which may lead to dense scar tissue and local end­

arteritic changes. These changes are remar­

kably similar despite their varied etiologic agents. The pathognomonic features, however, are either circular, ovoid, or kidney shaped

granules. These granules vary from 0.5 to 2 mm in diameters. Their color varies according to the etiologic agent. They are usually identi­

fied in proximity to the abscesses, and are dis­

charged periodically from the wound/sinus.

The interwoven colonies of fungal hyphae, with a fibrin shell derived from the host are charac­

teristic. The granules may get fragmented by the suppurative reaction. These fragments may then be carried by the macropha ges, produc­

ing new colonies. In eumycetomas, the fungus appears ramified and displays 2 to 4 mm vesi­

cular hyphae. Actinomycosis madurae, Nocardia rosatti, Madurella mycetomi and Strepto myces pel­

litieri granules in sections show a fairly specific morphology, and are easy to charac terize by a mycologist.

TReATMenT

The response to therapy is variable, and depends chiefly on the etiologic agent and duration of the disease. The treatment princi ples, thus, differ in different mycetomas. The drug of choice for actinomycotic mycetoma is sulfonamide. It is given as 6 to 8 gm daily in 4 divided doses for several weeks (Table 16.2). Alternative drugs are penicillin, tetracycline, chlo ramphenicol, and rifampicin. Diaminodi phenyl sulfone has been found to be effective in infections due to Nocardia brasiliensis. The eumycotic mycetomas are refrac tory to treat ment. Amphotericin­B shows poor results with a high incidence of side effects, as is ketoco nazole. In advanced cases surgical resection with plastic repair may be the only alternative.

SPOROTRICHOSIS

Sporotrichosis is a chronic, subcutaneous lym­

p hatic mycosis caused by Sporothrix schenckii resulting in indolent ulcers along the lymphatic

Figure 16.1: Madura foot

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Textbook of Clinical Dermatology channels of the limbs. Sporothrix schenckii is a di­

morphous fungus that grows on decaying veg­

etable matter such as timbers in underground mines. It is introduced into the skin through minor traumas such as thorn pricks/splinter in­

juries. The lesion is usually produced after 8 to 30 days of inoculation.

Sporotrichosis is a disease of both tropical and temperate climates. The disease shows seasonal variations, and is more active in a humid environ­

ment with temperatures ranging between 16 and 20°C. Initially, it was reported in America; since then it has been reported the world over. The largest number of cases from one single area has been reported from mining area of Johannesburg.

It has been reported to affect male farmers, laborers, and horticul turists. Occasionally, it may occur in women and children.

Clinical Features

Cutaneous lymphatic sporotrichosis, the most common presentation of the disease, forms an important differential diagnosis of leg ulcers.

It usually starts as a small papule over the foot or ankle following injury, which soon breaks down to form a shallow ulcer. These are asymp­

tomatic, and recalcitrant to treatment. So­called sporotri chotic chancre persists for several months, fol lowed later by the development of new nodules arising in line with the draining lymphatic channels (Fig. 16.2). The nodules occasionally sup purate, discharging scanty thin pus and forming a shallow circular ulcer. They are chara cteristically attached to the underlying lymp hatic channel, which is firm and nonten­

der. After several years, swollen regional lymph nodes may break down to form sinuses.

Occasionally, fixed sporotrichosis of the loca­

lized cutaneous variety may be seen. This is due to lack of spread through lymphatics.

Diagnosis

Deep mycoses, syphilis, tularemia, glanders, anthrax, pyogenic lesions, skin tuberculosis, staphylococcal lymphangitis and drug eruption are to be differentiated. Chain of lesions along lymphatic channels, chronicity, and benign nature are its clinical hallmarks. However, its diagnosis is confirmed by harvesting fungus on Sabouraud’s dextrose agar, which displays moist, white colonies with a wrinkled surface. The colonies gradually darken to brown or black color. Sporotrichin test is usually positive. Histopathology is unhelpful;

nevertheless, it must be done in each case. It reveals minute intraepidermal abscesses within a hyperplastic epidermis. In the dermis, an inflammatory infil trate is formed by neutrophils, lymphocytes, plasma cells, and small granulomas, and minute abscesses are seen.

Treatment

Oral iodides are the treatment of choice for cuta­

neous lymphatic sporotrichosis. An aqueous saturated potassium iodide solution is given as 1 ml, 3 times a day in milk or water. The dose is gradually built to 3 to 4 ml three times a day.

It should be continued for 3 to 4 weeks after an apparent recovery. The use of potas sium iodide is empirical, as it has been seen that Sporothrix schenckii can grow in a medium containing 10 percent potassium iodide.

Figure 16.2: Sporotrichosis

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Deep Mycotic Infection

The application of moist heat and a rubi facient used alone or in combination is also useful. It is reported to cure the lesions in a period of 3 to 16 weeks (Table 16.2).

CHROMOMYCOSIS

Chromomycosis or verrucous dermatitis is cha ra c terized by insidious development of verru coid, papillomatous excrescences confined to the skin and subcutaneous tissue of the feet and legs. It is caused by species of closely related fungi producing identical morphology.

They are Phialo phora verrucosa, Phialophora pedro soi, Fonsecaea compacta, Phialophora dermati­

tidis, and Clado sporium carrionii. Soil and wood are their natural habitats. They are introduced traumatically into human tissue. The incubation period varies from a few months to a few years.

It was first reported in Brazil in 1894. It is an uncommon deep mycotic infection confined to the tropics and subtropics—Central, South, and North America, Cuba, Jamaica, and Martinique.

Isolated cases have also been found in India, South Africa, Madagascar, Australia, and Northern Europe. Adult male farm workers and laborers, whose occupation brings them into intimate contact with soil, are chiefly affected.

However, children and women may also be affec ted by it. All races are susceptible, although most of the cases have been described in Cauca­

sians of North America. Person­to­person and animal­to­human transmission does not occur.

Clinical Features

A warty papule develops at the site of inocula­

tion, which gradually ulcerates and/or enlarges

Table 16.2: Treatment of deep mycosis

Disease Drug of choice Mode of administration and Other drugs

duration of treatments

Mycetoma

• Actinomycotic Sulfonamides 6 to 8 gm of sulfadiazine or its Penicillin, tetracycline, and

mycetoma derivatives is given daily for chloramphenicol may be

several weeks after the signs of administered along with sulfonamide

the disease have disappeared. to ensure a complete cure.

Co-trimoxazole 800 mg of sulphamethoxazole + Diaminodiphenyl sulfone (200 to

160 mg of trimethoprim daily, 300 mg) (DDS) is effective in

for a requisite period schizomycetomas due to

N. brasiliensis.

• Eumycotic Surgical resection Amphotericin B has been tried,

mycetoma and plastic repair though the results are poor.

Sporotrichosis Potassium iodide An aqueous saturated solution Amphotericin B

weeks after an apparent recovery

Chromo- Amphotericin B In localized lesions, 5 mg/mL Calciferol, iodides, thiobendazole, blastomycosis in 2 percent lidocaine is injected 5-fluorocytosine.

intralesionally.

Ketoconazole 400 to 800 mg daily for

requisite period

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Textbook of Clinical Dermatology

to form a brownish, black verrucous plaque with a raised border. Ulceration occurs in the plaque, discharging scanty serous exudate.

Eventually, the lesion becomes a dry, verrucoid, hyperkera totic mass grossly deforming the foot and accounting for the name ‘Mossy Foot’ (Fig. 16.3). New crops of satellite warty papules emerge in the vicinity of this plaque.

The disease is asymp tomatic, but secondary infection may cause some degree of pain and itching. The underlying bone and muscles are not invaded and are spared. However, in extreme involvement, the deeper lymphatics may be affected. Their blockage is responsible for the secondary elephantiasis.

Diagnosis

The disease is to be differentiated from blasto­

mycosis, which is characterized by a sharply delineated advancing border and central atro­

phic healing. Tertiary gummatous syphilis,

yaws, leishmaniasis, cutaneous tuberculosis, other fungal granulomas, neoplasms, and other causes of chronic leg ulcers are also to be differ­

entiated from chromomycosis.

Diagnosis is clinched by the clinical picture, isolation of the fungus on culture, and its demon stration on a histopathologic tissue section. Microscopic examination of the tissue section reveals features suggestive of foreign body granuloma, within which are areas of abscess formation. Epidermis shows moderate to marked hyperplasia, which may occasionally turn into pseudoepitheliomatous hyperplasia.

Keratolytic abscesses may be formed in the hypertrophic epidermis. The dermis shows extensive infiltra tion with polymorphous gra­

nu lation tissue, numerous multinucleated giant cells, and neutro philic microabscesses. Despite areas of tuber culoid formation, there is no caseation necrosis. When infection spreads to subcutaneous tissue, several abscesses lined by fibrous walls are formed. Hematoxylineosin or PAS stains identify the fungus lying either free in the granulomas or within giant cells. Occasio­

nally, transepidermal migration of fungal spores may occur.

Treatment

Excision followed by plastic repair can be performed in early lesions. Localized lesions may respond to amphotericin B. Recently oral ketoconazole has emerged as the treatment of choice. Calciferol, iodides, thiobendazole, and 5­fluorocytosine have also been tried (Table 16.2).

ReCOMMenDeD ReADIng

1. Sehgal VN, Jain S, Sing N. Porotrichosis. J Dermatol 1996;23:517­525.

Figure 16.3: Chromomycosis

Cutaneous tuberculosis has recorded an inc­

rease in its incidence recently. This has largely coincided with the general decline in pulmo­

nary tuberculosis in developed countries. The current situation in the Indian subcontinent seems to approximate that of developed coun­

tries of the temperate regions of the globe.

Hence, it is imperative to study the pattern of cutaneous tuberculosis in the tropics, which may not only help in defining its status but also enrich teaching.

Causative Microorganisms

Mycobacterium tuberculosis, Mycobacterium bovis, and Bacillius Calmette Guerin occasionally are responsible for cutaneous tuberculosis.

Route of Infection

It may either be the result of the following:

• Exogenous inoculation

– Primary chancre, in the absence of hyper­

sensitivity to tubercle bacillus

– Lupus vulgaris (LV) and tuberculosis ver ru cosa cutis (TBVC) in a presensitized host.

• Endogenous spread through

– Contiguous extension (autoinoculation) resul ting either in scrofuloderma or tuber ­ culosis cutis orificialis (TBCO)

– Lymphatics, resulting in lupus vulgaris in previously sensitized individual

In document La Sagra Toledana, un espacio de oportunidades entre influencias metropolitanas: propuesta de Plan de Ordenación Territorial (página 168-176)