History

Fact Explanation
Severe itching in in the groin and upper medial thigh This infection is caused by fungi of the genus Trichophyton,Microsporum, and Epidermophyton. These invade keratinized tissue such as the stratum corneum.The metabolic products and delayed hypersensitivity reactions cause inflammation [1] which gives rise to pruritus.
Well demarcated,erythematous plaques with raised,scaly edges Active fungal infection is present in the area close to the margin while the center is healing. Erythema is due to the vasodilation and raised edges are due to the exudation and edema.Inflammatory mediators also contribute to this.
Occasional pustules and vesicles Scratching causes a breach in the epithelium,allowing for colonization by bacteria such as Staphylococci.This causes superadded bacterial infection.
History of nail deformities,Crumbling and itching in toes. This is a dermatophyte infection of the nails (Tinea unguium).This could be the primary source of infection[3][4]
Scaling of soles or interdigital space This is termed Tinea pedis (dermatophyte infection of feet), this may be the primary site of infection[3][4]. People sharing showers or using communal swimming pools can get infected.[1]
Physical activity that increases sweating in the groin or wearing tight underwear. Sweating provides the moisture needed[4] for fungal growth.[5] Tinea cruris is commoner among males, because of the higher amount of sweat production.
History of recurrence or history of exposure to spores Spores are the mode of transmission.[2] Direct contact with an infected person (anthropophilic )[4] or indirect contact with items contaminated with the fungus, (clothing, towels, bedclothes) are significant. [4]
Work associated with soil, or animals Soil or animals[2] such as dogs, cats, guinea pigs, and cattle[4] act as reservoirs for the fungi. Walking bare foot, having pets or working on a farm can increase the chance of infection.
Immunocompromised states Immune response is associated with Type-4 hypersensitivity and impaired T cell function. In diseases associated with cell-mediated immunity HIV/ AIDS, corticosteroids results in chronic advanced infections.[5]
Dry skin Patients with atopy related dermatological conditions have dry skins.They can develop chronic Tinea infections.[5]
References
  1. WELLER Richard et al. Clinical Dermatology. 4th ed. Oxford. Wiley Blackwell. 2008. Pg248-252.
  2. Drake LA et al. Guidelines of Care for Superficial Mycotic Infections of the Skin:tinea corporis, tinea cruris, tinea faciei, tinea manuum, and tinea pedis. Guidelines/Outcomes Committee-American Academy of Dermatology J Am Acad Dermatol. 1996;34:282–286
  3. BROWN Robin Graham, BURNS Tony. Dermatology Lecture Notes.10th ed.Sussex. Wiley Blackwell. 2011. Pg30-35
  4. Fungal skin infection-foot. National Institute of Clinical Excellence Guidelines. 2013 [viewed 10 April 2014] Available from: http://cks.nice.org.uk/fungal-skin-infection-foot#!topicsummary
  5. QADIM Hamideh Herizchi. Factors leading to dermatophytosis. Annals of Parasitology. 2013. vol59(2), pg99–102

Examination

Fact Explanation
Well demarcated, asymmetrical plaques with erythema and raised borders in the groin, upper medial thighs or perineum The infection starts in the skin folds of groin and the spreads to the thighs[1][2] and buttocks. Scrotum and penis are rarely involved.[3]
Occasional pustules and vesicles This is due to secondary bacterial infection due to Staphylococci that colonize the skin. Bacteria can invade via the breaches in the epidermis produced by scratching.
Nail deformities Tinea unguium presents with yellowish nails with brittle margins, subungal hyperkeratosis and nail separation. Can be seen in a few toes. This may also be the primary site of infection.[1][2]
Signs of Tinea pedis Inter digital scaling or diffuse involvement of the sole, can be identified. This is the commonest primary site of infection. Transmission via spores occurs when the patient touches the groin following cleaning or trimming the nails.[1][2]
References
  1. WELLER Richard et al. Clinical Dermatology. 4th ed. Oxford. Wiley Blackwell. 2008. Pg248-252.
  2. BROWN Robin Graham, BURNS Tony. Dermatology Lecture Notes.10th ed.Sussex. Wiley Blackwell. 2011. Pg30-35
  3. Drake LA et al. Guidelines of Care for Superficial Mycotic Infections of the Skin:tinea corporis, tinea cruris, tinea faciei, tinea manuum, and tinea pedis. Guidelines/Outcomes Committee-American Academy of Dermatology J Am Acad Dermatol. 1996;34:282–286

Differential Diagnoses

Fact Explanation
Candidaiasis The area of infection is moist. Erythema is present[1]and is uniform without any central clearance[3].Body folds appear macerated.There is scaling and satellite papulopustules in the surrounding area.There are other sites of Candidaiasis such as arm pit,under the breast.[1]
Erythrasma This is due to Diptheroids that produce porphyrins. This is usually symptomless.[1] This is a uniformly brown lesion without an active margin. There may be slight scaling,[3] macules with wrinkles, and macerations in skin folds. Common under arm pits, groin and interdigital spaces.[1]Woods light produces brilliant coral red color[3].These features help to differentiate this from Tinea cruris.
Psoriasis Psoriasis of flexures can be mistaken for Tinea cruris. It is not scaly but a well demarcated plaque with erythema and glistening is present.There is fissuring in the folds and skin flexures are common sites. This is more commonly seen in women and the elderly.There may be other signs such as pitted nails, involvement of knee, elbow, and scalp[3].
Seborrhoeic dermatitis This can occur in skin-folds such as armpits, groin, central chest,upper back. Typical salmon-pink flat ,scaling, lesions with exudative eruptions are seen which are annular in shape. Pruritus is a variable feature. [2]
Neurodermatitis This is due to skin damage caused by repeated friction or scratching. There is a single, fixed plaque with itch and lichenification. Common sites are nape of neck, legs and the anogenital area. May even be be recurrent in some.[1]
References
  1. WELLER Richard et al. Clinical Dermatology. 4th ed. Oxford. Wiley Blackwell. 2008. Pg248-252.
  2. Seborrhoeic dermatitis. Derm Net NZ. DermNet New Zealand Trust. 2014 [viewed 8 April 2014] Available from: http://www.dermnetnz.org/dermatitis/seborrhoeic-dermatitis.html
  3. Fungal Skin Infection- Body and Groin. Clinical Knowledge Summaries. National Institute for Health and Care Excellence. [viewed 17 April 2014] Available from: http://cks.nice.org.uk/fungal-skin-infection-body-and-groin#!diagnosissub:2

Investigations - for Diagnosis

Fact Explanation
Potassium hydroxide preparation (KOH) A scraping of the scaly lesion is taken from the active border or the roof of the vesicle. In pustules, the purulent debris can be used.The specimen is kept on a glass slide and 10% to 15% KOH is added. Afterward s fungal stain to highlight the hyphae is also added. A positive test shows septate hyphae.[1],[2] This is investigation is indicated in an unclear diagnosis or poor responders to topical therapy and before starting oral anti fungals. [4]
Fungal cultures Sabouraud’s glucose agar is the culture medium used. The addition of chloramphenicol, inhibits bacterial overgrowth that may inhibit the growth of pathogenic dermatophytes. A color change will indicate the presence of dermatophytes. This investigation may take several days to give a result, thus is not widely performed.[1],[2] Is indicated in an unclear diagnosis or poor responders to topical therapy and before starting oral anti fungals. [4]
Wood's light Ultraviolet light emits a specific color depending to the fungi being examined. For example Microsporum will emit a green color during examination.[3] This is used differentiate tinea from Erythrasma, (in intertriginous disease and the scrotum) [1] because in Tinea cruris, there is no visible color difference.[4]
Bacterial culture To identify any secondary infection.[1]
Skin biopsy Useful for the differentiation of dermatophytes and other dermatoses.[1]
References
  1. Drake LA et al. Guidelines of Care for Superficial Mycotic Infections of the Skin:tinea corporis, tinea cruris, tinea faciei, tinea manuum, and tinea pedis. Guidelines/Outcomes Committee-American Academy of Dermatology J Am Acad Dermatol. 1996;34:282–286
  2. WEINSTEIN,Andrew. BERMAN,Brian.Topical Treatment of Common Superficial Tinea Infections. [Online]. Am Fam Physician. 2002 May 15;65(10):2095-2103. [viewed 17 April 2014] Available from: http://www.aafp.org/afp/2002/0515/p2095.html
  3. WELLER Richard et al. Clinical Dermatology. 4th ed. Oxford. Wiley Blackwell. 2008. Pg248-252.
  4. Fungal Skin Infection- Body and Groin. Clinical Knowledge Summaries. National Institute for Health and Care Excellence. [viewed 17 April 2014] Available from: http://cks.nice.org.uk/fungal-skin-infection-body-and-groin#!diagnosissub:2

Management - General Measures

Fact Explanation
Patient education Educate the patient about the condition state that it is a fungal infection and that it can be treated successfully. Patients hygiene is important in preventing transmission and recurrence.
Areas likely to become infected should be dried completely prior to dressing This prevents the presence of moisture that helps fungal growth may also reduce recurrence and superadded bacterial infection. [1]
Patients should also be advised to avoid walking barefoot Humans can acquire dermatophytes from the soil.[1]
Avoid sharing garments The fungal spores can be present in the clothes. [1]
Wash clothes and bed linen For the eradication fungal spores that can be present in the cloths. [2]
Loose fitting garments made of cotton Fungi grow rapidly in moist warm environments. Advise to choose socks that do not allow moisture to build up. [1]
Moisturiser Patients with dry skin can develop chronic Tenia infections.
References
  1. WEINSTEIN,Andrew. BERMAN,Brian.Topical Treatment of Common Superficial Tinea Infections. [Online]. Am Fam Physician. 2002 May 15;65(10):2095-2103. [viewed 17 April 2014] Available from: http://www.aafp.org/afp/2002/0515/p2095.html
  2. Fungal skin infection-foot. Clinical Knowledge Summaries. National Institute of Health and Care Excellence. 2013 [viewed 10 April 2014] Available from: http://cks.nice.org.uk/fungal-skin-infection-foot#!topicsummary

Management - Specific Treatments

Fact Explanation
Topical anti fungals Topical clotrimazole, econazole, or miconazole can be used for mild, non-extensive disease. These drugs are fungistatic.They interferes with cytochrome p 450 system.[2] Topical ketoconazole and topical terbinafine can be used as alternatives.[1]
Topical corticosteroids For skin that is inflamed ,a mildly potent topical corticosteroid ( hydrocortisone 1%),can be used in addition to the topical anti fungals[1] in order to reduce the inflammation.
Oral anti fungals Oral treatment can be considered if the patient is an adult with extensive disease, or has failed to respond to topical treatment. Recommendations: A positive microscopy or a positive culture /If negative but clinically diagnosed, repeat the test and start treatment.[1]Terbinafine is well tolerated and has less drug interactions. This is a fungicidal drug.It inhibits fungal squalene epoxidase.[2] Consider prescribing itraconazole or griseofulvin as alternatives to Terbinafine.[1] Oral itraconazole is fungistatic. It interferes with cytochrome p 450 system.[2]
Treat tenia pedis This is the primary site of infection.Topical nail preparations with amorolfine or ticonazole can be used. Ciclopirox is an alternative.[2]
References
  1. Fungal skin infection-foot. Clinical Knowledge Summaries. National Institute of Health and Care Excellence. 2013 [viewed 10 April 2014] Available from: http://cks.nice.org.uk/fungal-skin-infection-foot#!topicsummary
  2. WELLER Richard et al. Clinical Dermatology. 4th ed. Oxford. Wiley Blackwell. 2008. Pg248-252.