Groin and inframammary dermatitis

Clinical features

Intertrigo is an inflammatory condition commonly found in the intertriginous skin folds and flexures. It can be caused by multiple different conditions within the inflammatory and infectious categories. Many healthcare providers use the word “intertrigo” synonymously with candida intertrigo (CI), so for simplicity, this chapter will mainly focus on intertrigo secondary to infection.

The intertriginous areas are susceptible to friction and excess moisture, leading to subsequent maceration and weakening of the epidermis, which increases the risk for secondary fungal and bacterial infections. This condition is often seen in the geriatric and disabled population or anyone who is bedridden with limited mobility. Other risk factors include obesity; hyperhidrosis; poor hygiene; incontinence; immunocompromised states (e.g., diabetes, HIV); excess irritation in the area (e.g., recurrent allergic contact dermatitis [ACD]); and hot, humid climates.

• Intertrigo has an insidious onset that often starts with pruritus, burning, and/or tingling within the skin folds. Patients often complain of excess sweating and an inability to keep those areas dry.

• Lesions initially present as moist, erythematous patches in areas of opposing skin, such as the inframammary folds, axillae, abdominal folds, and groin. Over time, erosions, maceration, and fissures may develop, and it is common to find more than one anatomic location affected by this condition.

• Secondarily infected areas may present with further signs of inflammation, such as pain, abscesses, vesicles, and crusting. Superimposed candidiasis can lead to foul-smelling lesions and is characterized by the presence of erythematous satellite papules and pustules.

• CI of the interdigital spaces is known as “erosio interdigitalis blastomycetica” (EIB) and often affects the web space between the third and fourth fingers or toes. Although associated with the same aforementioned risk factors, EIB often occurs in people whose occupations involve frequent contact with water. These lesions range from mild or asymptomatic to intensely erythematous and malodorous with maceration, fissures, desquamation, and ulceration.

Differential diagnosis

The differential diagnosis for intertrigo includes inverse psoriasis, tinea cruris, erythrasma, ACD, and seborrheic dermatitis.

• Inverse psoriasis ( Fig. 5.1 ) is a variant of psoriasis that presents as well-demarcated, erythematous plaques, notably found in the intertriginous skin folds. Whereas classic psoriatic lesions often have micaceous or silvery scale, inverse psoriasis often lacks this because of the moist environment. The lesions may also be more symptomatic with associated pruritus and discomfort from fissuring and maceration. CI often has pathognomonic satellite papules and pustules, which are not seen in inverse psoriasis. A potassium hydroxide (KOH) preparation of skin scrapings will be negative for hyphae in inverse psoriasis. Lesions improve with topical calcipotriene, tacrolimus, and mild nonfluorinated topical steroids (for a limited time only to prevent skin atrophy).

  

• Tinea cruris is a dermatophyte infection that is commonly known as “jock itch.” It is characterized by well-defined erythematous plaques in the skin folds of the groin or medial thighs and most commonly affects young men. A KOH preparation will show the presence of hyphae. Tinea cruris is treated with topical antifungal agents, but it often recurs.

• Erythrasma is a bacterial infection characterized by symmetric, well-demarcated plaques in the groin, axilla, and interdigital web spaces. Erythrasma is diagnosed based on a physical examination and coral-red fluorescence with a Wood lamp test. It typically appears less inflammatory than intertrigo and can be treated with topical antibiotics (such as clindamycin solution or erythromycin cream).

• ACD sometimes occurs in association with intertrigo and presents with scaly, erythematous patches, occasionally with vesiculation, that can spread beyond the intertriginous skin. The physical examination findings, in combination with a positive exposure history, can help distinguish this from intertrigo. Treatment includes topical steroids and avoidance of the contactant agent.

• Seborrheic dermatitis can occur in association with intertrigo or in isolation. Sharply demarcated erythematous plaques can be seen in the skin folds of the axilla, groin, and inframammary region. When seborrheic dermatitis presents in a more classic distribution, such as on the scalp, face, and ears, the lesions tend to have more yellowish, greasy scale. This may be less obvious, however, in the intertriginous areas because of the excess moisture. Diagnosis is usually made based on a physical examination, and the condition can be treated with ketoconazole cream.

Work-up

Intertrigo is a clinical diagnosis based on a physical examination and history. A skin biopsy may be done to exclude other potential conditions but is generally not indicated.

• A full skin examination is recommended to identify the involved areas.

• KOH can be used to confirm the presence of a superimposed infection. If pustules, crusting, abscesses, or vesicles are present, a culture from the affected areas should be done to identify the cause of secondary infection.

• A Wood lamp test can also be used to rule out erythrasma. The latter would show a bright coral red fluorescence when the lamp is shone over the affected area.

• A history of contactants, such as past creams, used to rule out a primary or secondary ACD is also recommended.

Initial steps in management

The most important step in management is elimination of aggravating factors because this can alleviate the severity of the intertrigo and potentially prevent recurrences. It is important to counsel patients because they may be frustrated by the chronic nature of the condition and the multiple relapses.

• Recommend the use of gentle cleansers with thorough drying afterward. Patients can use a hair dryer on a low cool setting to minimize any excess moisture. The affected areas should be exposed to the air as much as possible.

• Antiperspirants and light, nonrestrictive cotton clothing are suggested to minimize sweating. Drying powders, such as aluminum sulfate, talcum, and calcium acetate, can be applied daily to help prevent recurrences. Gauze can be placed between the skin layers, if needed, to keep them dry and reduce friction.

• For those with hyperhidrosis, referral to dermatology is recommended to discuss treatments that may help decrease sweating, such as glycopyrrolate, topical aluminium chloride, and injections of botulinum toxin.

• Barrier creams that contain zinc oxide and/or petrolatum can be applied to affected areas to minimize frictional irritation and skin breakdown.

• For significant pruritus, a low-potency topical steroid cream (hydrocortisone 2.5%) may be applied twice daily for 10 to 14 days. Patients should be counseled on the potential side effects, such as skin atrophy, striae, and dyspigmentation. Combination antifungal and topical steroid formulations are not recommended because these contain higher potency steroids with an increased risk for cutaneous side effects.

• Management of common comorbidities, such as diabetes and obesity, can reduce the risk for recurrence.

CI or other associated fungal infections should be treated using topical antifungals. Creams are generally preferred for an active infection, whereas the powder may be useful as maintenance therapy to prevent recurrences.

• Azole treatments (ketoconazole, clotrimazole, miconazole, and econazole) can be applied twice daily for 2 to 4 weeks or until the infection resolves.

• Nystatin cream can be applied twice daily until resolution, but it is only effective in the treatment of intertrigo caused by Candida infection.

• Other antifungal treatment options include butenafine 1% cream, naftifine 2% cream, and terbinafine 1% cream, which can be applied once or twice daily.

• For resistant CI, oral fluconazole may be considered; however, a referral to dermatology is recommended to confirm the diagnosis.

Secondary bacterial infections should be treated promptly to avoid further complications.

• If a bacterial infection is a clinical consideration, a culture should be done to identify the offending agent and determine the appropriate treatment.

• Mild infections can be treated with topical antibacterials, such as mupirocin and erythromycin, depending on the pathogen.

• Oral antibiotics, such as first-generation cephalosporins, erythromycin, or penicillin may be prescribed depending on the severity of the infection and the bacterial species present.

If the treatment response is inadequate, reconsider the diagnosis and refer to dermatology for further evaluation.

Warning signs/common pitfalls

• Because this condition can be secondary or occur concurrently with other diseases, dermatology referral is important to establish the correct diagnosis.

• Secondary infection is a common occurrence in intertrigo. Patients should be referred to dermatology for management to minimize the risk for infection because this can progress to cellulitis or sepsis if untreated.

• Patients with intense pruritus can be prescribed a low-potency topical steroid cream. These agents should be used sparingly and for a limited time only because of potential cutaneous side effects.

• The use of topical agents may cause ACD, which can be alleviated by discontinuing the use of the offending agent.

Counseling

You have a condition called intertrigo, which is caused by friction, moisture, and lack of ventilation in the folds of your skin. Maintaining proper hygiene and keeping the areas dry can alleviate your symptoms and prevent the risk for recurrent infection. Use gentle cleansers to keep the area clean and apply powder to keep the folds dry while exposing the skin to air as much as possible. Apply antiperspirants, wear loose-fitting cotton clothing, and avoid excessive heat to minimize irritation and sweating because these may exacerbate your condition. Creams containing zinc oxide can be used to create a physical barrier and reduce friction. If you have diabetes, maintaining tight control of your blood sugar can decrease the risk for intertrigo and secondary infection. In addition, maintaining a healthy weight can also be beneficial.

Contact your healthcare provider if the affected areas start to ooze or develop a foul smell because these are potentially signs of a superimposed infection that may need to be treated with antibiotics or topical creams.

Clinical features

Erythrasma is caused by the gram-positive bacillus Corynebacterium minutissimum, which infects the most superficial layer of the skin, the stratum corneum. C. minutissimum is a normal inhabitant of the skin; in the setting of excess heat and moisture, however, it can pervade the intertriginous sites of the body. Other contributing factors include obesity, diabetes, hyperhidrosis, lack of hygiene, and immunosuppression. Deeper/systemic infections by this bacterium are exceedingly rare outside of the setting of immunosuppression.

• The classic clinical feature is a well-demarcated, hyperpigmented or erythematous, reddish-brown patch. There may be accentuation of skin lines and some fine scale. The most commonly affected sites are the web spaces of the toes, the upper inner thighs, the inguinal folds, the scrotum/vulva, the axillae, and the gluteal cleft.

• Examination in a dark room with a Wood lamp demonstrates coral pink changes at the sites of erythrasma.

• The infection can last for years if left untreated. Although it can be itchy, it is normally asymptomatic.

Differential diagnosis

The main clinical differential diagnoses are tinea corporis/pedis/cruris, intertrigo, cutaneous candidiasis, tinea versicolor, and seborrheic dermatitis. Complicating matters, the bacterial and fungal diseases can coexist, as will be discussed in a later section. Inverse psoriasis is also in the differential.

• Tinea corporis normally presents with an annular, elevated, scaly border with central clearing. Erythrasma normally does not have an annular appearance. A skin scraping stained with KOH should be positive in the setting of tinea, and a Wood lamp examination should not show the coral pink changes.

• Tinea versicolor normally presents as a disseminated hyperpigmented or hypopigmented macular eruption with minimal scale on the trunk, which may involve the intertriginous sites as well. A KOH test will also be positive in this setting.

• Candidiasis normally presents with a deeper red plaque with satellite lesions and pustules. A KOH can be performed to detect yeast forms. Routine culture is also useful. Erythrasma normally is not deep red in color and lacks the satellite lesions/pustules.

• Seborrheic dermatitis can also involve the groin folds; however, it would typically present with significantly more scale that is waxy as opposed to fine. The red patches would typically be present on the head and neck, the axillae, and the central chest.

• Inverse psoriasis presents with well-demarcated red plaques with wet, macerated scale in intertriginous sites. Fissuring can occur. The scale in erythrasma is much finer and typically not macerated. Completing a family history of psoriasis, inquiring about joint pains, and performing a complete examination to look for other signs, such as extensor surface plaques, scalp involvement, and nail changes, can be useful.

Work-up

A thorough physical examination that focuses on the aforementioned sites is recommended. Other corynebacterial diseases, such as pitted keratolysis, can be present in patients with erythrasma.

A Wood lamp examination of the lesions will reveal the characteristic coral pink (red) hue from the organism releasing porphyrins. Nevertheless, this test may be falsely negative if the patient recently washed the area.

A KOH test will be negative for yeast and hyphae. A Gram stain can be performed; however, the yield is poor and it is not generally recommended.

Concomitant infections of erythrasma and tinea corporis/pedis/cruris, as well as tinea versicolor, can occur and are common, so a combination of the aforementioned techniques is important for guiding diagnosis and treatment.

A biopsy can be performed; however, it should not be needed unless there is a failure of treatment that calls the clinical diagnosis into question. Of note, the histopathologic features of erythrasma are subtle, and the bacteria can be easily missed in the stratum corneum by a pathologist. Therefore the clinical concern should be stated on the pathology requisition to help guide interpretation.

There is no role for blood work unless recurrent widespread erythrasma is present, in which case screening tests for diabetes should be considered.

Initial steps in management

Warning signs/common pitfalls

There can be postinflammatory pigment alteration after many intertriginous dermatoses. The hyperpigmentation from these disorders can mimic erythrasma and vice versa. Because it is asymptomatic and can look like postinflammatory pigment change, erythrasma can be dismissed as a resolved issue, leading to a delay in diagnosis and treatment.

Obese patients or physically impaired patients may be unaware of the infection, particularly because of the lack of symptoms. Examining folds thoroughly, especially ones that patients cannot examine themselves, is important.

Groin rashes are often empirically treated as fungal infections without consideration for this common bacterial infection. The previously described work-up should be used, especially if a patient has failed empiric topical and/or oral antifungal agents.

Counseling

You have a superficial bacterial infection of the skin that is known as “erythrasma.” Unless you have an impaired immune system, this infection is not serious or life threatening. The bacteria like to grow in dark, warm, moist areas on your body. The infection can be easily treated by keeping these areas dry and cool and using topical antibiotics, such as erythromycin or clindamycin.

Recurrences of erythrasma are very common, particularly in warmer, wetter climates, or if there is a lack of access to proper hygiene. If you have frequent recurrences, we should screen you for diabetes. If you do not improve after initial treatment, oral antibiotics, such as erythromycin, clarithromycin, or amoxicillin-clavulanate, can be used to treat your condition.

Clinical features

Lichen sclerosus (LS) is an inflammatory disorder of the skin that presents in children and adults, primarily affecting the anogenital skin of females and males ( Fig. 5.2 ). Females are more often affected than males. LS can present less commonly with widespread extragenital lesions ( Fig. 5.3 ). The cause of LS is unknown. In the early inflammatory stage, the lesions may lack characteristic features, but there are certain classic features to note in general.

• The classic lesion shows a white (ivory to porcelain) macule/papule or patch/plaque, sometimes with scattered central petechiae/purpura and a slightly hyperpigmented border. The lesions may be flush with the skin, slightly elevated, or, in the chronic stage, atrophic. They often have a parchment paper–like appearance. The atrophy often feels superficial, with underlying induration, particularly in long-standing lesions.

• Plugging of hair follicles and/or sweat glands may occur, causing a textured, rather than smooth, appearance.

• Maceration, erosions, bullae, and purpura are often seen. Vulvar lesions can take on a thickened (hyperkeratotic) appearance.

• Chronic, untreated lesions can scar, inducing fusion of the labia and shrinking of the vaginal introitus in women, and phimosis in uncircumcised men. Scarring of the urethral meatus can also occur.

• The lesions may be asymptomatic; however, pain and pruritus are commonly described, particularly in genital sites. There can be associated dyspareunia and dysuria. In uncircumcised males, balanitis can occur.

• Urinary retention secondary to scarring of the urethral meatus can also result in pyelonephritis.

• Patients with chronic genital lesions have up to a 5% increased risk for developing squamous cell carcinoma (SCC). SCC in extragenital LS is rare.

• LS often waxes and wanes; however, it can resolve spontaneously, particularly in younger patients with limited genital involvement. The extragenital variant can be more challenging and persistent in its course.

Differential diagnosis

The main clinical differential diagnoses for LS are lichen planus, morphea, vitiligo, sexual abuse/trauma, extramammary Paget disease (EMP), and SCC in situ/invasive SCC.