Mushrooms among us? Dermatophyte infections, mimetics and treatment… (2023)

SUMMARY

• Ringworm is a common skin condition seen in general practitioners' offices, but it's often misdiagnosed and can be mistaken for imitations.
• Unlike other fungi, dermatophytes metabolize keratin for energy and are generally not particularly virulent.
• Ringworm is more common in black and Asian patients, has a predilection in young adults, and is three to four times more common in men.
• Clinical dermatophyte infections are usually named after the affected area of ​​the body.
• First-line treatment includes topical agents such as azoles, allylamines, ciclopirox, butenafine, and tolnaftate, but the treatment of choice for tinea capitis and tinea barbae is griseofulvin.
• Scabies is caused by the mite,Sarcoptes scabiei, and should be considered in the differential diagnosis, but the distribution and appearance of the lesions are usually characteristic.
• Treatment for scabies involves two topical applications of 5% permethrin cream seven days apart.

Ringworm refers to a superficial fungal infection of the skin, hair, and nails caused by dermatophytes. Dermatophytes are filamentous fungi; The three genera that cause disease areMicrosporum,Tricofiton, YouEpidermophyt.¹ Trichophyton rubrumIt is the most common cause of dermatophyte infections, accounting for almost 70% of infections worldwide.¹These infections are extremely common, but are more prevalent in warm tropical climates. Ringworm is more common in black and Asian patients, has a predilection in young adults, and is three to four times more common in men.¹Dermatophyte infections are similar in their physiology, morphology and pathogenicity and are clinically referred to as "ringworm".

Transmission can be anthropophilic (human-to-human), zoophilic (animal-to-human), or geophilic (soil-to-human/animal).¹Unlike other fungi, dermatophytes metabolize keratin as a source of energy. They are not particularly virulent and usually only invade the outer horny layers of the epidermis. Mannans in the cell wall of dermatophytes contribute to skin invasion, reduce epidermal proliferation, and exhibit immunosuppressive effects.¹Skin barrier defects (diseases such as Darier, Hailey-Hailey, and ichthyosis) or maceration tend to favor dermatophyte invasion.¹Host protective factors that limit penetration into keratinized tissue include protease inhibitors, sebum, serum factors, and the host immune system.¹Immunodeficient hosts (chronic mucocutaneous candidiasis, common variable immunodeficiency, and HIV) tend to have more severe, chronic, or recurrent infections than immunocompetent hosts.

Dermatophyte infections are often misdiagnosed in clinical practice. The clinical presentation of these infections can vary, and many other skin conditions can have a similar presentation. This review will facilitate a more accurate diagnosis of dermatophyte infections and provide the most up-to-date treatment regimens.

Tinea infection subtypes

Clinical dermatophyte infections are usually named after the affected body part. Clinical subtypes include tinea corporis (body), tinea capitis (scalp), tinea cruris (groin), tinea pedis (feet), tinea manuum (hands), tinea unguium (nails), tinea barbae (beard), and tinea faciei ( Face). ). 🇧🇷 See figure 1 for the clinical presentation of tiña manuum. See Table 1 for clinical features of tinnitus and its imitations.

body moths

Body ringworm is an infection of body surfaces other than the palms or soles, groin, face, scalp, hair, and nails. It usually occurs on exposed skin of the trunk and extremities and is usually confined to the epidermis. It is usually acquired through direct contact or transmitted secondarily from another infected area of ​​the body.¹The most common pathogen isrot, followed byT. mentagrophytes.¹infection withscissors t.It can occur in adults through contact with a child with tinea capitis.²Direct contact with an infected cat or dog can lead to contaminationDogs Microspore.²This infection is found worldwide; However, it is more common in tropical regions. The classic presentation is known as "ringworm" and is characterized by an itchy, erythematous, scaly patch with a raised edge and a central glenoid.³Figure 2 shows the mycosis on the side of the neck.

Clinical variants of tinea corpus

Majocchi granuloma is a rare and deep infection of the hair follicle that invades the dermis or subcutaneous tissue.²Triggering events include leg shaving, skin trauma, or immunosuppression. It is characterized by perifollicular papulopustules or granulomatous nodules.¹Deep mycosis results from excessive inflammation in response to dermatophyte infection. It may have a granulomatous or verrucous appearance and be mistaken for cutaneous tuberculosis or squamous cell carcinoma.¹

The imbricata tiña (Tokelau tiña) is a chronic infection caused byT. concentricand is characterized by concentric, scaly, annular, erythematous plaques.¹Found in equatorial regions of the world.

Tinea Corpus-Imitato

The following conditions can mimic tinea of ​​the body: Dermatitis (including nummular eczema [see Figure 3], stasis, atopic, contact and seborrheic eczema), pityriasis versicolor, pityriasis rosea, parapsoriasis, centrifugal annular erythema, perforating serpiginous elastosis, annular psoriasis, annular granuloma, subacute lupus erythematosus (see Figure 4), mycosis fungoides and impetigo.¹

I have headache

Tinea capitis is a dermatophytic infection of the scalp that primarily affects children. The peak age is 3 to 7 years and is more common in children.³ scissors t.is responsible for more than 90% of tinea capitis in the United Statesdogas the second most common cause.¹Other etiologies includeT. violaceum(endemic to Africa) andM. audiences(Europa).¹Tinea capitis can have different clinical presentations depending on the pathogen and the host's immune response. Alopecia with or without scales is the most common manifestation; However, it can range from mild scaling to a severe pustular rash with alopecia called a kerion.¹

The three invasive patterns of dermatophytes infecting hair include endothrix, ectothrix, and honeycomb. The Endotrix pattern is the result of anthropophiliaTricofitonInfection within the hair shaft, and common causes arescissors t.jT. violaceum.¹Ectotrix patterns occur when the infection is outside the hair shaft and leads to the destruction of the cuticle. Presentation ranges from non-inflamed, scaly, patchy alopecia to the formation of kerions. Microspore infections can fluoresce under the Wood lamp. The honeycomb pattern is created byT. schoenleiniiand it is the most serious. It appears as a thick yellow crust and fluoresces bluish under a Wood lamp.¹Scarring alopecia can develop when the infection is chronic. It is important to note that many scalp/hair conditions can cause dandruff or alopecia and it is very important to consider and rule out a yeast infection.

Imitation of tinea capitis

Seborrheic dermatitis, alopecia areata, psoriasis, and trichotillomania can mimic tinea capitis. When pustules are present, pyoderma gangrenosum and folliculitis may resemble tinea capitis.¹If scarring is present, lichen planus, discoid lupus erythematosus, and centrifugal central scarring alopecia should be part of the differential diagnosis.¹

leg ringworm

Commonly known as jock itch, tinea cruris is a dermatophyte infection of the groin area. It is usually seen on the inner thighs and thigh creases, but it can also be seen on the buttocks and gluteal crease. The three most common pathogens arerot,E. floccosum, YouT. mentagrophytes.¹It is more common in men because the scrotum provides an ideal environment and because men are more likely to coexist with tinea pedis, which can be transmitted to the groin by putting on underwear.¹Characteristically, the lesions are sharply demarcated with a raised, erythematous, scaly leading edge. The lesions may be vesicular and unilateral or bilateral. In men, the scrotum is usually preserved. Healthcare professionals should consider cutaneous candidiasis if the scrotum is affected.¹

Tinea Leg-Imitator

The following conditions can mimic tinea cruris: reverse psoriasis, erythrasma, seborrheic dermatitis, intertrigo candidiasis, contact dermatitis, lichen simplex chronicus, parapsoriasis, Hailey-Hailey disease, and Langerhans cell histiocytosis.¹

Fussmotte

Tinea pedis, also known as athlete's foot, is the most common site of dermatophyte infection. Infection usually occurs on the soles of the feet, most commonly in the interdigital areas. 🇧🇷See Figure 5.) The main types of tinea pedis are interdigital, hyperkeratotic (moccasin-like), vesiculobulous (inflammatory), and ulcerative. The characteristic finding in the interdigital type is itchy and erythematous scales and/or erosions, usually appearing between the third and fourth fingers. Moccasin tinea pedis presents as a diffuse, erythematous, hyperkeratotic lesion covering the soles and the medial and lateral margins of the feet. 🇧🇷See Figure 6.) The vesiculobullous type presents as an erythematous vesicular or bullous rash that may be itchy or painful and most commonly occurs on the medial aspect of the foot. Similar to tinea cruris are the most common responsible pathogensrot,E. floccosum, YouT. mentagrophytes.¹Patients can also have a secondary bacterial infection if they have foul-smelling erosions or ulcerations.

Tinea manuum has a characteristic appearance of unilateral hyperkeratotic lesions on the palms and interdigital spaces.^1,4The most common pathogens are tinea pedis and tinea cruris, and these infections often occur together.

Tinea Pedis Mimic

Mimics of tinea pedis include dermatitis (dyshidrotic and contact), psoriasis vulgaris or pustular, secondary syphilis, pitted keratolysis, hereditary palmoplantar keratosis, and juvenile plantar dermatosis.^1,3Erythrasma, or bacterial infection, can resemble the interdigital type of tinea pedis.¹

Onychomycosis

Ringworm is a dermatophytic infection of the nail unit most commonly caused byrot,T. mentagrophytes, YouE. floccosum.¹This infection is often referred to as onychomycosis, a generic term that includes all nail fungal infections, including non-dermatophytic causes. However, dermatophytes account for about 90% of onychomycosis cases. Tinea unguium is more common in men, is often associated with chronic tinea pedis, and is more common on toenails than fingernails. It can be unilateral or bilateral and can affect just one nail or multiple nails. Depending on the entry point of infection, there are three common patterns. The distal/lateral subungual type is the most common and shows onycholysis, yellowing, and thickening of the nails.¹(See Figure 7.) The superficial white type is restricted to the dorsal surface of the nail and appears as white patches (T. mentagrophytes) or striped cross bands (rot).¹The proximal subungual type penetrates below the proximal nail fold and is usually found in immunocompromised patients.¹

Tinea unguium mimic

Numerous pathogens (dermatophytes and non-dermatophytes) cause onychomycosis, and many factors can cause nail dystrophy, making accurate diagnosis difficult. Diagnoses that may mimic ringworm include candida infections, nail manifestations of psoriasis, lichen planus, dermatitis, hyperthyroidism, external trauma, pachyonychia, and Darier's disease.¹Tinea unguium can be difficult to treat due to the long treatment times required, drug side effects, and recurrences.

Mycosis of the face

Tinea faciei is a dermatophytic infection of the skin of the face and is usually caused by the same organisms as tinea corporis.⁴infections withrotDiagnosis can be particularly difficult because the edges of the lesion are often indistinguishable. Tinea faciei is more commonly seen in AIDS patients.

Tinea Faecii-Imitatoren

Seborrheic, perioral, or contact dermatitis can mimic facial tinea. Other mimics include rosacea, lupus erythematosus, acne, and annular psoriasis in children.¹

Bartspur

Tinea barbae occurs exclusively in the beard hair distribution on the face and neck of men. It is commonly transmitted by animals, and typical pathogens includeT. mentagrophytesjT. Wache.¹The clinical presentation can be severe in zoophilic pathogens and often presents as intense inflammation, pustules, and abscesses with bacterial superinfection.⁴ rotcauses a slight surface variation similar to tinea corporis.

Tinea barbae mimic

Bacterial folliculitis, herpes simplex/zoster, acne vulgaris, and cervicofacial actinomycosis can mimic tinea barbae.¹

Diagnose

The most important factor in diagnosing a dermatophyte infection is a thorough physical examination. It is important to remember that more than one area of ​​the body can be infected at the same time, requiring a thorough examination of the skin. For example, tinea pedis often occurs with tinea unguium or tinea cruris.²

Clinical findings suggestive of dermatophyte infection should be followed by confirmatory testing. The diagnosis is usually confirmed with a potassium hydroxide (KOH) test using microscopy or fungal culture. KOH tests can be improved by staining with Chlorazole Black E. The disadvantage of the KOH test is that it often gives false negative results.⁵A skin scraping for KOH examination should be taken from the active edge of the lesion with a #15 blade.⁶The provider should apply alcohol to the lesion prior to scraping to improve debris adhered to the blade.

All dermatophytes appear the same on KOH scans. When a specific species needs to be identified, culture is required. Fungal cultures are grown in Sabouraud's medium, which allows identification of fungal species.³Cultures are slow growing and require several weeks of incubation.⁷If the KOH test and fungal cultures are negative and dermatophyte infection is still suspected, a skin biopsy may be done. Skin biopsies show fungal hyphae within the stratum corneum. Periodic Acid Schiff Stain (PAS) (see Figure 8) and silver stain are commonly used to enhance fungal elements in biopsy specimens. Techniques using polymerase chain reaction (PCR) and mass spectroscopy can also be used to identify strains of dermatophytes.⁸PCR is a fast, simple, and highly specific method for diagnosing dermatophyte infections.⁹There are also promising studies for the immunochromatographic diagnosis of dermatophytes.¹⁰The most reliable method for diagnosing onychomycosis is histological examination of a nail plate fixed in formalin and stained with PAS.¹The doctor places a cut nail in formalin and sends it to the local pathology lab for evaluation.

treatment

The first-line treatment for uncomplicated, superficial, and localized tinea infections (corporis, cruris, and pedis) is topical antifungals. Topical agents include azoles (clotrimazole, econazole, ketoconazole, efinaconazole, luliconazole, miconazole, oxiconazole, sertaconazole, sulconazole), allylamines (naftifine, terbinafine), cyclopirox, butenafine, and tolnaftate.²Some of these topical preparations are available without a prescription and are often an adequate treatment for minor infections. The azoles tend to be more economical although not as effective as the allylamines.⁶Topical antifungals should be used once or twice daily for two to four weeks and continued for one week after clinical approval.⁶It is important to note that while topical nystatin is effective in treating Candida, it is not effective in dermatophyte infections.²Photodynamic therapy is also a treatment option when other methods have failed.⁶

Infections including tinea manuum, tinea capitis, tinea unguium and Majocchi's granuloma; large-scale infections; and infections that fail topical treatment often require systemic antifungal medication. Oral agents include terbinafine, fluconazole, itraconazole, and griseofulvin. Prescribing guidelines for widespread infection, topical treatment failure, and recurrent infection recommend terbinafine 250 mg daily for 14 days, fluconazole 50 mg daily for two to four weeks (six weeks for tinea pedis), or 150-200 mg once weekly for two to four weeks four weeks, Itraconazole 100 mg daily for 15 days or 200 mg daily for seven days (tinea pedis and manuum may require longer treatment) or griseofulvin in micro-sizes of 500-1000 mg daily for two to four weeks.^2,6

The treatment of choice for tinea capitis and tinea barbae is griseofulvin. Terbinafine, itraconazole, and fluconazole are not FDA approved for the treatment of tinea capis or barbae.¹Adjunctive treatment for tinea capitis includes antifungal shampoo (2% ketoconazole or 2.5% selenium sulfide every other day), disinfection of cleaning equipment, and treatment of close contacts.¹In addition to antifungal treatment, products containing urea, glycolic acid, and lactic acid can be used to treat tinea pedis or tinea pedis.^1,11Tinea unguium can be extremely difficult to treat and often requires long-term systemic treatment.

Mycosis incognita is a condition that occurs when a dermatophyte infection is misdiagnosed and treated with a topical corticosteroid. It can alter the clinical presentation of the infection and complicate diagnosis. Treatment with corticosteroids can also make the infection worse and cause Majocchi granuloma.²The use of topical corticosteroids in conjunction with antifungal medications is not recommended, although it may result in faster resolution of inflammation and disease.²

Sarna

scabies mite,Sarcoptes scabiei var. of man, causes human scabies.¹²(See Figure 9.) The entire life cycle of the mite takes place in the epidermis, with the female mite laying three eggs daily. These eggs mature over the course of 10 days. Mites generally live on the human host for less than three days, except in the case of crusted scabies where they can survive up to seven days.¹²Crusted scabies is a type of scabies found in people with compromised immune systems that allows the mite to survive with minimal symptoms and large numbers of mites.¹²

Scabies skin lesions have a typical distribution. They commonly affect the finger webs, the flexion of the wrists, the neck, and the navel. Men usually have lesions on the penis and scrotum, while women are more likely to have lesions on the vulva and areola. The burrow is the classic and characteristic clinical finding of scabies and represents the female mite's oviposition route. Clinically, the duct appears as a small white to gray convoluted plaque.¹²Construction may not always be present.¹²Other skin findings may include erythematous papules, pustules, or vesicles, often with significant excoriations. 🇧🇷See figures 10 and 11.) Diagnosis can be confirmed by skin scraping, curettage, or microscopic examination of an affected area. A skin biopsy can confirm the diagnosis.¹²Figure 12 shows a skin biopsy from a scabies infestation.

Symptoms of scabies can appear two to six weeks after the first exposure, or within a day or two after the second exposure. The main symptoms are itching and skin lesions. Scabies is commonly known as one of the most itchy skin rashes. Itching can be made worse by a hot bath or cause insomnia as it is worse at night. Household contacts also often cause itching.

Standard treatment for scabies can be completed with two topical treatments of permethrin 5% cream seven days apart (application on day 1 and day 8).¹²In adults, the cream is applied to all skin surfaces from the neck down in the evening and washed off in the morning. In elderly patients and infants (from 2 months), the cream should also be applied to the face and scalp. Patients with sensitivity or allergies to formaldehyde or chrysanthemum should avoid using permethrin cream. Other topical medications to consider for scabies if you are resistant or allergic to permethrin are lindane 1% lotion/cream, sulfuric ointment (5-10%), and crotamiton 10% lotion/cream. Ivermectin (200 to 400 mcg/kg) orally is also an excellent option for resistant scabies and is treated on day 1 and day 8 or 14.¹²Ivermectin can cause central nervous system (CNS) toxicity in infants and young children. Lindane also has potential CNS toxicity in patients weighing less than 50 kg.¹²Therefore, these drugs are used only when absolutely necessary.

scabies mimics

lichen planus lesions (See Figure 13) have a typical appearance on the flexor wrists, but are flat-topped purplish papules, often with a reticulated white veil, and do not have the characteristic gait of scabies. Other mimics may include viral rashes, guttate psoriasis, secondary syphilis, drug reactions, or other arthropod attacks.

Conclusion

Dermatophyte infestations and scabies are very common around the world and are often misdiagnosed. Many other dermatological skin conditions can mimic these infections. A thorough skin examination can often provide clues to the diagnosis. Other laboratory modalities, such as skin swab, biopsy, or culture, may further aid in the correct diagnosis. If the therapies discussed above do not treat the rash, it is always advisable for primary care physicians to refer the dermatologist for further evaluation and treatment.

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