The menace of fixed drug combination containing salicylic acid, dithranol, and coal tar in superficial dermatophytosis – A case series

INTRODUCTION

Superficial dermatophytosis has taken the shape of an epidemic in recent years, with chronic, recurrent, and steroid-modified lesions being on the rising trend. The hallmarks of this epidemic have been described as extensive lesions, involvement of uncommon sites, atypical morphology, undue chronicity, frequent recurrences, and therapeutic slow or non-response.^[1] An important fact contributing to this epidemic is the procurement of over-the-counter (OTC) medications. Apart from topical steroid-containing creams, the fixed drug combination (FDC) containing salicylic acid (1.15%), dithranol (1.15%), and coal tar (5.3%), initially marketed as an anti-psoriatic cream, is one of the most common OTC drugs to be procured for superficial dermatophytosis. We are presenting a case series of superficial dermatophytosis that was modified and complicated secondary to the FDC application.

CASE SERIES

The first case [Figure 1a], a 32-year-old male, presented with a well-defined erythematous, edematous plaque with mild peripheral scaling associated with severe burning sensation. The lesion had developed following the use of the FDC containing salicylic acid (1.15%), dithranol (1.15%) and coal tar (5.3%) for 5 days continuously in a patterned distribution over the exact application site. The FDC was applied as part of the topical treatment for an itchy, scaly, well-defined plaque consistent with tinea corporis. There was no history of any other form of topical or oral treatment for the same. Similarly, the second case [Figure 1b], a 40-year-old male, presented with a sudden onset of diffuse bright erythema and burning sensation following application of the FDC for 2 days for the treatment of tinea lesion over the left groin. The third case [Figure 1c] presented with the sudden development of bright erythema, edema, and burning on the right cheek following application of the FDC for recurrent tinea faciei, which was earlier treated with topical antifungals. The fourth case, a 38-year-old male, presented with follicular papules [Figure 2a] and mild erythema with post-inflammatory hyperpigmentation [Figure 2b] following application of the FDC on and off for recurrent tinea cruris. The patient did not give a history of any other topical treatment other than the FDC. The fifth case [Figure 3a], a 35-year-old female, presented with multiple painful erosions with crusting on the buttocks over a background of central clearing and peripheral post-inflammatory scaling and hyperpigmentation suggestive of a resolving irritant contact dermatitis. The patient gave a history of the FDC application over the tinea lesion for around 10 days with initial erythematous reaction over the application site, subsequently complicated with painful lesions, leading to dermatology consultation. A gram stain from the erosions showed clusters of gram-positive cocci suggestive of Staphylococcal infection. The sixth case [Figure 3b] presented as a lichen simplex chronicus-like presentation with thick scaling, following long-term application of the FDC. The seventh case [Figure 3c], a 26-year-old female, presented with almost clearing of the tinea lesions with post-inflammatory scaling and hyperpigmentation following the FDC application for 7 days. Initially, she had mild erythema and stinging sensations, although she continued the topical drug.

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Figure 1:

Tinea corporis complicated and modified as bright erythema, edema, and burning sensation on (a) abdomen, (b) groin, and (c) face.

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Figure 2:

Tinea cruris complicated with (a) minimal erythema and (b) folliculitis.

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Figure 3:

(a) Tinea cruris presenting as erosion, crusting, and post-inflammatory hyperpigmentation and (b) lichenified plaque, and (c) tinea corporis showing signs of healing with post inflammatory hypopigmentation.

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All patients had procured the FDC directly from the pharmacy without a proper dermatologist consultation. They were diagnosed as irritant contact dermatitis to the FDC, along with superficial folliculitis and secondary infection in cases three and four, respectively. A potassium hydroxide mount was positive for dermatophytes in four out of seven patients. The patients were treated with topical emollients and mild topical corticosteroids (for a maximum of 7 days) for the acute erythema and burning sensation, followed by proper antifungal treatment. The patients presenting with secondary bacterial infection were treated with appropriate antibiotics.

DISCUSSION

Anthralin/dithranol and coal tar have been in use for the treatment of chronic plaque psoriasis since the 19^th century.^[2,3] The basic mechanism of action in psoriasis is suppression of deoxyribonucleic acid synthesis and keratinocyte proliferation, and preventing T-cell activation. The major side effects noticed are application site burning, irritation, erythema, and stinging. The FDC containing dithranol (1.15%), salicylic acid (1.15%), and coal tar (5.3%) showed a good response in chronic plaque psoriasis when used for a short contact period of 30 minutes a day.^[4]

The casual treatment-seeking behavior of patients and non-strict drug regulatory policies have made this FDC a common cream for superficial dermatophytosis, often recommended by pharmacists, quacks, family members, and friends, finally leading to irritant contact dermatitis. The incidence of using preparations containing dithranol, coal tar, and salicylic acid for superficial dermatophytosis varies from 3.85% to 14.7% as seen in different studies.^[5,6] Rajagopal et al. presented 15 cases of tinea with irritant contact dermatitis secondary to mostly dithranol and salicylic acid.^[7] The common presentations were burning, pain, hyperpigmented patch/ plaque, erythema, erosion, exfoliation, scaling, vesiculation, and crusting, and rarely lid edema, lichenification, and even erythroderma. In our case series, burning was the most common symptom. The presenting clinical signs included erythema, scaling, follicular papules, erosions, crusting, lichenification, and post-inflammatory hyperpigmentation. Two cases showing signs of clearing of the tinea lesion may be attributed to the keratinolytic and exfoliative effects of dithranol and salicylic acid, respectively. Weekly, once, salicylic acid (30%) peel for 4 weeks has been tried in superficial dermatophytosis, showing a clinical and microbiological cure in 88% of patients after 1 week, but the recurrence rate was as high as 41% after 4 weeks of treatment.^[8] This modality of treatment was unjustifiable due to a smaller number of patients, a high recurrence rate, and a very superficial mode of action of salicylic acid to be recommended in recurrent dermatophytosis, where foci of infection are folliculocentric.^[9] Dermatophyte infection has a local inflammatory response due to the release of proinflammatory cytokines by keratinocytes secondary to dermatophyte antigens. The exaggerated inflammatory response presenting as irritant contact dermatitis secondary to dithranol and other irritants has been attributed to the direct biochemical toxicity to keratinocytes and activation of toll such as receptors and nucleotide-binding oligomerization domain like receptors, leading to release of proinflammatory cytokines (Interleukin [IL]-1a, IL-1b, tumor necrosis factor-alpha, and IL-6) and chemokines.^[7]

The treatment includes a short course of topical/systemic steroids to suppress the inflammation secondary to the irritant contact dermatitis, followed by a proper antifungal therapy. Secondary bacterial infections need to be treated with proper antibiotics, as in one of our cases.

CONCLUSION

The wide variety of presentations of superficial dermatophytosis being modified and complicated by the application of the FDC containing dithranol, salicylic acid, and coal tar, implicates a high index of suspicion and a detailed history taking regarding all the topical preparations used by the patient. It also highlights the need to create awareness against OTC medications for dermatophytosis, leading to an epidemic of chronicity and a high recurrence rate. Early intervention and appropriate management ensure a favorable outcome.