Spot the Rash

11-year-old female presents with worsening facial rash

Colleen H. Cotton
Marissa J. Perman
Figure 1. Annular pink plaque with fine scale at the edge, click here to see larger image.
Source: Marissa J. Perman, MD

An 11-year-old healthy female presented to the dermatology clinic for evaluation of a facial rash that had lasted for 3 weeks. Initially, it was a round, scaling papule treated by another provider with combination betamethasone dipropionate 0.05%/clotrimazole 1% cream, but the rash worsened. This was followed by mupirocin ointment, without improvement. She has since been using triamcinolone 0.025% ointment for the last 4 days and feels it is enlarging (Figure 1). It is not painful but is mildly itchy.

She had a history of “dry, rashy skin” in infancy. She has no pets at home and participates in gymnastics. On exam, there was a pink, annular, peripherally scaling plaque. Within the plaque, there were two pink papules. There were no other rashes noted on full body skin examination.

Can you spot the rash?

A. Nummular eczema

B. Tinea faciei

C. Allergic contact dermatitis

D. Granuloma annulare

E. Psoriasis

Case Discussion

Tinea faciei (choice B) describes a dermatophyte infection on the face. It appears as annular plaques with a leading edge of scale and inflammatory border, although initially it may be round without central clearing. The lesions tend to expand over weeks, and new lesions may develop as the fungus spreads superficially on the skin. It may be confused with bacterial infection or inflammatory skin lesions. The condition is termed “tinea incognito” when it has been treated with topical corticosteroids because this can alter the classic appearance and make diagnosis more difficult. Topical steroids reduce inflammation, which may temporarily improve pruritus, but they allow the fungus to thrive, particularly if the topical steroid is of mid to high potency. This treatment can also drive the dermatophyte infection deeper into the skin and hair follicles, resulting in a dermal fungal infection known as Majocchi’s granuloma, which appears as inflammatory papules. Facial lesions make up a disproportionate amount of tinea incognito and Majocchi’s granuloma cases compared with other parts of the body.

Several methods can help to establish the diagnosis of tinea faciei. A potassium hydroxide preparation taken from the active inflammatory edge of the plaque may show hyphae under the microscope. Biopsy will also demonstrate hyphae in the stratum corneum, as well as in and around the hair follicles if Majocchi’s granuloma exists. Periodic acid-Schiff and Grocott-Gomori’s methenamine silver stains may help to visualize the fungal elements. Fungal culture is the least sensitive method for diagnosing tinea, but it can still be helpful if positive. Dermatophyte screens are often more effective than fungal cultures because they screen only for dermatophytes. The most common causative dermatophytes are Trichophyton species like T. tonsurans, T. rubrum and T. mentagrophytes.

Uncomplicated tinea faciei may be treated with topical azole antifungals. However, if the condition has been treated with topical steroids or involves hair-bearing areas (eg, eyebrows, sideburns), topical therapy is insufficient. Oral antifungals for a minimum of 2 to 4 weeks are required. Terbinafine is generally considered first-line therapy for Trichophyton infections, with griseofulvin, itraconazole and fluconazole as additional options. If other family members or pets have any skin lesions suspicious for tinea, they should be evaluated and treated to minimize the risk for recurrent infection.

Allergic contact dermatitis (ACD) can cause geometric inflammatory plaques. Lesions are often very pruritic and may having blistering, weeping or crusting. Topical corticosteroids are the treatment of choice, as well as identifying and avoiding causative allergens. Central clearing and a leading edge of scale are not characteristic of this condition. In our patient, her rash worsened with exposure to topical corticosteroids. Although ACD may continue to worsen with exposure to the culprit allergen, ACD caused by topical corticosteroids or preservatives in these medications is rare.

Nummular eczema is a variant of atopic dermatitis. This is a chronic skin condition with thick, coin-shaped plaques that are often crusted and extremely pruritic. It may require stronger topical steroids than those used for classic atopic dermatitis in the flexural areas. Although the patient has a possible history of atopic dermatitis in infancy, a single nummular plaque arising at this age in the absence of another skin rash would not be consistent with nummular eczema. Lesions of nummular eczema also usually do not have the type of delicate scale appreciated here.

Granuloma annulare (GA) is often mistaken for tinea because the lesions are also made up of annular papules and plaques. These can occur as single or multiple lesions, most commonly on acral surfaces. There may be associated comorbidities more commonly seen in adults with GA, including diabetes or HIV infection, but the condition usually occurs in otherwise healthy patients. GA does not have any associated scale or epidermal change, which distinguishes it from tinea.

Psoriasis is another chronic inflammatory skin condition that can be seen in childhood. Facial involvement is more common in children than in adults. A lack of rash in other classic sites such as the umbilicus, scalp, extensor knees and elbows and gluteal cleft make a solitary plaque on the face unlikely to be psoriasis. The scale of psoriasis is also thicker, adherent and more silvery than the fine, flaky scale of tinea.

When examining a circular or annular inflammatory rash on the face, tinea is important to consider. Use of topical steroids may mask the classic appearance of tinea. If tinea is on the differential, potassium hydroxide prep, dermatophyte screen or fungal culture may be helpful in making the diagnosis. Additionally, topical antifungals will not worsen an inflammatory dermatosis, but topical steroids may necessitate oral antifungal treatment if tinea is missed.

Disclosures: Cotton and Perman report no relevant financial disclosures.

Colleen H. Cotton
Marissa J. Perman
Figure 1. Annular pink plaque with fine scale at the edge, click here to see larger image.
Source: Marissa J. Perman, MD

An 11-year-old healthy female presented to the dermatology clinic for evaluation of a facial rash that had lasted for 3 weeks. Initially, it was a round, scaling papule treated by another provider with combination betamethasone dipropionate 0.05%/clotrimazole 1% cream, but the rash worsened. This was followed by mupirocin ointment, without improvement. She has since been using triamcinolone 0.025% ointment for the last 4 days and feels it is enlarging (Figure 1). It is not painful but is mildly itchy.

She had a history of “dry, rashy skin” in infancy. She has no pets at home and participates in gymnastics. On exam, there was a pink, annular, peripherally scaling plaque. Within the plaque, there were two pink papules. There were no other rashes noted on full body skin examination.

Can you spot the rash?

A. Nummular eczema

B. Tinea faciei

C. Allergic contact dermatitis

D. Granuloma annulare

E. Psoriasis

PAGE BREAK

Case Discussion

Tinea faciei (choice B) describes a dermatophyte infection on the face. It appears as annular plaques with a leading edge of scale and inflammatory border, although initially it may be round without central clearing. The lesions tend to expand over weeks, and new lesions may develop as the fungus spreads superficially on the skin. It may be confused with bacterial infection or inflammatory skin lesions. The condition is termed “tinea incognito” when it has been treated with topical corticosteroids because this can alter the classic appearance and make diagnosis more difficult. Topical steroids reduce inflammation, which may temporarily improve pruritus, but they allow the fungus to thrive, particularly if the topical steroid is of mid to high potency. This treatment can also drive the dermatophyte infection deeper into the skin and hair follicles, resulting in a dermal fungal infection known as Majocchi’s granuloma, which appears as inflammatory papules. Facial lesions make up a disproportionate amount of tinea incognito and Majocchi’s granuloma cases compared with other parts of the body.

Several methods can help to establish the diagnosis of tinea faciei. A potassium hydroxide preparation taken from the active inflammatory edge of the plaque may show hyphae under the microscope. Biopsy will also demonstrate hyphae in the stratum corneum, as well as in and around the hair follicles if Majocchi’s granuloma exists. Periodic acid-Schiff and Grocott-Gomori’s methenamine silver stains may help to visualize the fungal elements. Fungal culture is the least sensitive method for diagnosing tinea, but it can still be helpful if positive. Dermatophyte screens are often more effective than fungal cultures because they screen only for dermatophytes. The most common causative dermatophytes are Trichophyton species like T. tonsurans, T. rubrum and T. mentagrophytes.

Uncomplicated tinea faciei may be treated with topical azole antifungals. However, if the condition has been treated with topical steroids or involves hair-bearing areas (eg, eyebrows, sideburns), topical therapy is insufficient. Oral antifungals for a minimum of 2 to 4 weeks are required. Terbinafine is generally considered first-line therapy for Trichophyton infections, with griseofulvin, itraconazole and fluconazole as additional options. If other family members or pets have any skin lesions suspicious for tinea, they should be evaluated and treated to minimize the risk for recurrent infection.

Allergic contact dermatitis (ACD) can cause geometric inflammatory plaques. Lesions are often very pruritic and may having blistering, weeping or crusting. Topical corticosteroids are the treatment of choice, as well as identifying and avoiding causative allergens. Central clearing and a leading edge of scale are not characteristic of this condition. In our patient, her rash worsened with exposure to topical corticosteroids. Although ACD may continue to worsen with exposure to the culprit allergen, ACD caused by topical corticosteroids or preservatives in these medications is rare.

Nummular eczema is a variant of atopic dermatitis. This is a chronic skin condition with thick, coin-shaped plaques that are often crusted and extremely pruritic. It may require stronger topical steroids than those used for classic atopic dermatitis in the flexural areas. Although the patient has a possible history of atopic dermatitis in infancy, a single nummular plaque arising at this age in the absence of another skin rash would not be consistent with nummular eczema. Lesions of nummular eczema also usually do not have the type of delicate scale appreciated here.

PAGE BREAK

Granuloma annulare (GA) is often mistaken for tinea because the lesions are also made up of annular papules and plaques. These can occur as single or multiple lesions, most commonly on acral surfaces. There may be associated comorbidities more commonly seen in adults with GA, including diabetes or HIV infection, but the condition usually occurs in otherwise healthy patients. GA does not have any associated scale or epidermal change, which distinguishes it from tinea.

Psoriasis is another chronic inflammatory skin condition that can be seen in childhood. Facial involvement is more common in children than in adults. A lack of rash in other classic sites such as the umbilicus, scalp, extensor knees and elbows and gluteal cleft make a solitary plaque on the face unlikely to be psoriasis. The scale of psoriasis is also thicker, adherent and more silvery than the fine, flaky scale of tinea.

When examining a circular or annular inflammatory rash on the face, tinea is important to consider. Use of topical steroids may mask the classic appearance of tinea. If tinea is on the differential, potassium hydroxide prep, dermatophyte screen or fungal culture may be helpful in making the diagnosis. Additionally, topical antifungals will not worsen an inflammatory dermatosis, but topical steroids may necessitate oral antifungal treatment if tinea is missed.

Disclosures: Cotton and Perman report no relevant financial disclosures.