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New curvilinear scars on the legs
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An 18-year-old male presents to pediatric dermatology with curvilinear scars on the legs. He reports having had several small, round areas of redness and scale on his right thigh about 6 months ago. The patient believed this to be a ringworm infection. As he and his family travel frequently to Mexico, he purchased — without a prescription — a medicated lotion called “Derma-Med,” touted for its antifungal properties. The patient applied the lotion twice a day to his legs for about 5 months and notes that “it did not do anything but make the itch better.” Additionally, he developed “scars all over his legs a few weeks ago.” He and his family are convinced these scars are the result of a recent cold he had. Of note, the patient had his last major growth spurt about 2 years ago. He is proud of having never done “anything athletic,” and he enjoys playing video games all day.
Emily Osier
Andrew C. Krakowski
On physical exam, we see an otherwise healthy teenage male, with normal heart rate and blood pressure, who appears somewhat anxious throughout the visit. He is of normal height and he does not demonstrate hypermobility or laxity of joints. He has normal hair and what feels like a normal thyroid. He has no signs of lymphadenopathy and no residual signs of his recent upper respiratory infection. He does not exhibit a “buffalo hump,” and he does not show signs of central obesity. Strikingly, he has multiple, scattered, linear, atrophic, pink-to-violet curvilinear scars on both his legs. He does have scant, thin, skin-colored curvilinear plaques on his upper arms, abdomen and lower back, which he states had developed a couple of years ago with his last major growth spurt. An annular, pink-to-red, scaly plaque is present on his right thigh.
Can you spot the rash?
Diagnosis: Exogenous corticosteroid
Case discussion
The patient’s initial rash on his right thigh was caused by tinea corporis (aka ringworm), as the family had correctly deduced. His fungal infection had not cleared despite months of topical therapy and was noted to persist on our exam, as seen in figure 1; microscopy with KOH and fungal culture confirmed this diagnosis.
Figure 1: Persistent fungal infection despite months of topical therapy was noted on exam. Figure 2: Leg lesions displaying striae rubrae distensae.
Image: Osier E
His subsequent leg lesions were a striking display of striae rubrae distensae as seen in figure 2, the differential diagnosis for which includes mechanical stretching of the skin (as seen with rapid weight gain, weight lifting, and pubertal growth spurts), post-pregnancy, Cushing’s syndrome, collagen vascular disorders like Ehlers-Danlos and Marfan’s syndromes, and exogenous topical corticosteroids. This patient denied weight lifting and had his main growth spurt 2 years earlier. He had normal-appearing, thin skin-colored striae in typical puberty-related locations, including the upper arms, abdomen and lower back. This indicates a propensity for his skin to develop striae in the first place. He had no other signs of Cushing’s syndrome or Ehlers-Danlos syndrome. As his new striae were confined solely to the legs in areas where he had directly applied his antifungal lotion, the diagnosis was fairly straightforward. So, what was in that topical antifungal lotion from Mexico?
Derma-Med is a combination therapy product consisting of clotrimazole, gentamicin and betamethasone dipropionate 0.05% cream. This “triple threat” combination product is commonly used as an antifungal medicament outside of the United States, and it is often available abroad without a prescription. This form of betamethasone is considered a high-potency, Class 2 topical corticosteroid, and prolonged application likely resulted in this patient’s striae.
The presence of a potent corticosteroid can help initially to decrease pruritus associated with tinea corporis, but it may, paradoxically, prevent complete clearing of the fungal infection. This may lead to prolonged application of the combination medication and a subsequent higher rate of adverse effects. A similar case involving the same combination medication was reported in which a pregnant patient applied the medication to treat tinea corporis on her arm. She developed wide, violaceous striae in the location of betamethasone application, more severe in appearance than her pregnancy-related striae. A review of a similar combination betamethasone and clotrimazole product reported several cases of persistent tinea infection despite therapy, similar to our patient’s experience.
Adrenal gland suppression, despite a lack of other physical signs or symptoms, was a concern in the current patient. He was referred to endocrinology and was safely weaned from his exogenous source of corticosteroids without further comorbidity. His striae, which form as a result of “breaks” in the connective tissue, may fade in color with time but, unfortunately, are unlikely to completely resolve.
Practitioners should be aware that treatment of dermatophyte infections with antifungal medications in combination with highly potent corticosteroids can lead to ineffective treatment, as well as adverse effects. We should also recognize that patients may travel internationally and may have access, either in person or through the Internet, to medications we would never think to use in combination with one another.
References:
Barkey WF. J Am Acad Dermatol. 1987;3:518-519.
For more information:
Emily Osier, MD, is a clinical research fellow in pediatric dermatology at Rady Children’s Hospital, San Diego. She can be reached at 8010 Frost St., Suite 602, San Diego, CA 92123; email: ejosier@gmail.com.
Andrew C. Krakowski, MD, is an attending physician at Rady Children’s Hospital, San Diego.
Disclosure: Krakowski and Osier report no relevant financial disclosures.