I have seen a ringworm on my face. I had wanted to apply clotrimazole cream but a colleague told me sertaconazole cream will be better. I know it is a ringworm because I am a health worker.Interesting enquiry.Tinea is a fungal infection of the skin. Tinea is also known as ringworm. This is because it can cause red patches on the skin in the shape of rings. But it is not caused by worms. Tinea infection can affect any part of the body. Tinea infections of the feet, nails, and genital area are not often called ringworm. This is because the red patches may not look like rings. But it most often occurs in moist areas of the body and around hair. The fungus can be spread from person to person.Different types of fungal (tinea) infections are named for where they occur on the body. The most common types areinclude Athlete’s foot (tineapedis), Jock itch (tinea cruris) occurs in the genital area. This condition is more common in men and rare in women. It happens more often in warm weather. There is Scalp ringworm (tinea capitis). Scalp ringworm occurs on the head. It is very contagious but rare in adults. It could affect the nail (tinea unguium)-toenails, fingernails. It causes thickened, deformed, and discoloured nails instead of a rash. There is Body ringworm (tinea corporis). This occurs anywhere on the body or the face. But it is more common in skin folds. It is also more common in warmer climates.The fungus is spread through direct contact with an infected person, infected objects (towels, clothing, and combs), an infected animal, or infected soil. It can take days or up to 2 weeks before you develop the infection after being in contact with the fungus. The fungi that cause ringworm can live for a long time on objects. Because of this, you may not know the exact source.
Tinea refers to scaly fungal infections of the epidermis and skin appendages caused by a group of keratinophilic fungi known as “dermatophytes” which includes three genera, namely, Epidermophyton, Microsporum, and Trichophyton. The two varieties of tinea most commonly encountered are tineacorporis and tineacruris.
Topical antifungals alone are usually sufficient for localized dermatophyte infections.Dermatophytes are group of taxonomically related fungi that invade the keratinized tissue (skin, hair, nails) of humans or other animals resulting in an infection called dermatophytosis.Tinea corporis is a superficial dermatophyte infection characterized by either inflammatory or noninflammatory lesions on the glabrous skin (i.e. skin regions other than the scalp, groin, palms, and soles).
Topical therapy is recommended for a localized infection because dermatophytes rarely invade living tissues. Topical azoles (clotrimazole, miconazole, econazole, sertaconazole) and allylamines (terbinafin) show high rates of clinical efficacy. The topical azoles inhibit the enzyme lanosterol 14-alpha-demethylase, a cytochrome P-450–dependent enzyme that converts lanosterol to ergosterol. Inhibition of this enzyme results in unstable fungal cell membranes and causes membrane leakage.
Allylamines (eg, naftifine, terbinafine) and the related benzylamine butenafine inhibit squalene epoxidase, which converts squalene to ergosterol. Inhibition of this enzyme causes squalene, a substance toxic to fungal cells, to accumulate intracellularly and leads to rapid cell death. Allylamines bind effectively to the stratum corneum because of their lipophilic nature. They also penetrate deeply into hair follicles.
Systemic therapy may be indicated if tinea corporis includes extensive skin infection, immunosuppression, resistance to topical antifungal therapy, or the comorbid presence of tinea capitis or tinea unguium.
Clotrimazole is a broad spectrum topical antifungal agent. It is generally well tolerated but in some cases erythema, burning, stinging, peeling, blistering, oedema, pruritus and urticaria at site of application are reported. It is applied twice daily for three weeks for T. corporis. Sertaconazole is a newer topical imidazole found to be more active than other azole antifungals. It is also reported that once daily application for three weeks regimen of Sertaconazole showed improved patient compliance which is important in successful treatment of dermatomycoses . The traditional azoles (e.g., clotrimazole, miconazole, ketoconazole) are fungistatic and need twice-daily application. The allylamines (e.g., terbinafine, naftifine) are fungicidal. The available topical formulation of terbinafine (1%) forms a reservoir in the upper epidermal layers which enable just once-daily application. Available literature indicates that superior cure rates and better compliance observed with terbinafine are attributable to its fungicidal action and the convenience of once-daily application.
Sertaconazole inhibits the synthesis of ergosterol, an essential component of fungal cell walls, resulting in disruption of mycelial growth and replication. At higher concentrations, sertaconazole binds directly to nonsterol lipids in the fungal cell wall, which leads to increased permeability and subsequent lysis of the mycelium. Thus, depending on the concentration, sertaconazole may exhibit both fungistatic and fungicidal activities. Sertaconazole is a newer azole and structurally unique due to a benzothiophene ring. It is the only azole with a fungicidal action due to its ability to cause direct fungal cell membrane damage. The available topical formulation of sertaconazole (2%) attains fungicidal concentration in the stratum corneum as the lipophilic property of the benzothiophene ring enables prolonged dermal retention. This permits just once-daily application contrary to most other topical azoles. Sertaconazole has additional anti-inflammatory and antipruritic actions. It has shown efficacy even against dermatophyte isolates resistant to other azoles. It has faster and superior cure rates as compared to other azoles (Dattatreyo et al. Efficacy and tolerability of topical sertaconazole versus topical terbinafine in localized dermatophytosis: A randomized, observer-blind, parallel group study. Indian J Pharmacol. 2016 Nov-Dec; 48(6): 659–664. doi: 10.4103/0253-7613.194850).
The clinical efficacy data shows that clinical cure rate and the mycological cure rate of 2% Sertaconazole cream twice daily was significantly greater than that of 2% miconazole cream twice daily in patients with a range of cutaneous mycoses(Liebel F, Lyte P, Garay M. Anti-inflammatory and anti-itch activity ofSertaconazole nitrate. Arch Dermatol Res. 2006;298(4):191–99. PubMed). Miconazole is another commonly available topical azole antifungal.
Fungal infections of the dermis may elicit a local inflammatory response that results in irritation and itching. Sertaconazole significantly reduced the release of several proinflammatory cytokines compared with a range of other antifungal agents tested (Kyle AA, Dahl MV. Topical therapy for fungal infections. Am J Clin Dermatol. 2004;5(6):443–51. PubMed). Sertaconazole 2% cream is better than Clotrimazole 2% cream in treating Tinea corporis. Most azole drugs are fungistatic, which, although limits fungal cell growth, does not prevent the shedding of viable mycelial cells from the skin surface. Sertaconazole however, has an additional fungicidal activity. In general, fungicidal drugs are preferred over fungistatic drugs for superficial dermatophyte infections because higher cure rates are achieved in shorter treatment times, thus increasing the likelihood of patient adherence and decreasing the incidence of recurrence.
EDWARD O. AMPORFUL