Why Are You Still Prescribing a 66-Year-Old Drug?

Several weeks ago, this 14-year-old boy developed an itchy spot on his neck. Concerned that the problem was “ringworm,” the boy’s grandfather took him to the primary care provider, who prescribed nystatin cream. This produced modest improvement in the appearance of the lesion but had no effect on the associated itching. At that point, they were referred to dermatology for further evaluation.

The patient denies any other skin problems. The only animal he has been exposed to is his own dog, who has been part of the household for years. The boy is not involved in contact sports (eg, football, wrestling), and he reports that none of his siblings or friends have any skin complaints.

He is otherwise healthy and does not take any prescription medications.

EXAMINATION
The “rash” consists of a single, 2-cm lesion on the patient’s anterolateral neck. It is perfectly round and slightly erythematous, with a cleared center and scaly advancing margin. Palpable adenopathy is evident just above the lesion. There are no other lesions elsewhere, and the patient’s skin is otherwise unremarkable.

What is the diagnosis?

DISCUSSION
A KOH prep revealed abundant fungal elements, confirming the diagnosis of tinea corporis. This conclusion had already been reached empirically by the primary care provider, who chose nystatin cream for treatment. When that drug faltered, diagnostic doubt reared its head. The KOH settled the question once and for all—a crucial step, since nystatin is often prescribed for conditions that have no likelihood of responding to it (eg, eczema, psoriasis, granuloma annulare).

Nystatin, a polyene antifungal, was discovered and brought to market in 1950—that’s nearly 66 years ago! At that time, very few antifungal agents were available, so nystatin gained instant acceptance practically overnight. Since then, although dozens of newer and better antifungals have come on the market, nystatin continues to be prescribed out of sheer habit. A lot of water has gone down the river since 1950!

Nystatin was first isolated and developed by two scientists (Brown and Fuller) who worked in the lab at the New York State Health Department in the ’40s and ’50s. A popular practice at the time was to collect soil samples from local farmers to see what bacteria could be isolated. Brown and Fuller found a unique species of Streptomyces that they named S noursei after the dairy farmer whose soil they sampled.

They noted that this organism exuded a substance that inhibited yeast, mold, and fungi in vitro; when this substance was isolated and purified, it worked topically as well. They named this substance nystatin in honor of their employer, the New York State Health Department.

As charming as this history is, in the intervening 60+ years, better antifungals have been introduced and organisms have become less responsive to nystatin. In my opinion, except for unusual selective instances, there is no reason to prescribe nystatin instead of imidazole and allylamine (eg, miconazole, terbinafine, or naftifine).

For this patient, I prescribed oxiconazole lotion for twice-daily application to this small and limited lesion. With more extensive disease, I might add an oral antifungal, such as terbinafine. The patient’s lesion should resolve in two weeks or less.

One final note: In dermatology, we discourage the use of the term ringworm because it contributes to the “ick” factor associated with “worms”—which are not even involved in tinea corporis.

TAKE-HOME LEARNING POINTS
• Nystatin is a 66-year-old relic that has no place in treating ordinary dermatophytosis.

• “Newer” antifungals are more effective and kill a wider range of organisms, including yeast and fungi.

• In my experience, most nystatin is prescribed for conditions that have no chance of responding to it (eg, eczema, psoriasis, or granuloma annulare), because a differential was not considered.

• Primary care offices that are comfortable doing wet preps for clue cells and trichomonas feel no such need to perform KOHs to confirm fungal infection, and so diagnostic confusion results.

• There is no medical entity called ringworm. This is lay terminology based on the misbelief that worms are somehow involved in tinea.

Several weeks ago, this 14-year-old boy developed an itchy spot on his neck. Concerned that the problem was “ringworm,” the boy’s grandfather took him to the primary care provider, who prescribed nystatin cream. This produced modest improvement in the appearance of the lesion but had no effect on the associated itching. At that point, they were referred to dermatology for further evaluation.

The patient denies any other skin problems. The only animal he has been exposed to is his own dog, who has been part of the household for years. The boy is not involved in contact sports (eg, football, wrestling), and he reports that none of his siblings or friends have any skin complaints.

He is otherwise healthy and does not take any prescription medications.

EXAMINATION
The “rash” consists of a single, 2-cm lesion on the patient’s anterolateral neck. It is perfectly round and slightly erythematous, with a cleared center and scaly advancing margin. Palpable adenopathy is evident just above the lesion. There are no other lesions elsewhere, and the patient’s skin is otherwise unremarkable.

What is the diagnosis?

DISCUSSION
A KOH prep revealed abundant fungal elements, confirming the diagnosis of tinea corporis. This conclusion had already been reached empirically by the primary care provider, who chose nystatin cream for treatment. When that drug faltered, diagnostic doubt reared its head. The KOH settled the question once and for all—a crucial step, since nystatin is often prescribed for conditions that have no likelihood of responding to it (eg, eczema, psoriasis, granuloma annulare).

Nystatin, a polyene antifungal, was discovered and brought to market in 1950—that’s nearly 66 years ago! At that time, very few antifungal agents were available, so nystatin gained instant acceptance practically overnight. Since then, although dozens of newer and better antifungals have come on the market, nystatin continues to be prescribed out of sheer habit. A lot of water has gone down the river since 1950!

Nystatin was first isolated and developed by two scientists (Brown and Fuller) who worked in the lab at the New York State Health Department in the ’40s and ’50s. A popular practice at the time was to collect soil samples from local farmers to see what bacteria could be isolated. Brown and Fuller found a unique species of Streptomyces that they named S noursei after the dairy farmer whose soil they sampled.

They noted that this organism exuded a substance that inhibited yeast, mold, and fungi in vitro; when this substance was isolated and purified, it worked topically as well. They named this substance nystatin in honor of their employer, the New York State Health Department.

As charming as this history is, in the intervening 60+ years, better antifungals have been introduced and organisms have become less responsive to nystatin. In my opinion, except for unusual selective instances, there is no reason to prescribe nystatin instead of imidazole and allylamine (eg, miconazole, terbinafine, or naftifine).

For this patient, I prescribed oxiconazole lotion for twice-daily application to this small and limited lesion. With more extensive disease, I might add an oral antifungal, such as terbinafine. The patient’s lesion should resolve in two weeks or less.

One final note: In dermatology, we discourage the use of the term ringworm because it contributes to the “ick” factor associated with “worms”—which are not even involved in tinea corporis.

TAKE-HOME LEARNING POINTS
• Nystatin is a 66-year-old relic that has no place in treating ordinary dermatophytosis.

• “Newer” antifungals are more effective and kill a wider range of organisms, including yeast and fungi.

• In my experience, most nystatin is prescribed for conditions that have no chance of responding to it (eg, eczema, psoriasis, or granuloma annulare), because a differential was not considered.

• Primary care offices that are comfortable doing wet preps for clue cells and trichomonas feel no such need to perform KOHs to confirm fungal infection, and so diagnostic confusion results.

• There is no medical entity called ringworm. This is lay terminology based on the misbelief that worms are somehow involved in tinea.

Several weeks ago, this 14-year-old boy developed an itchy spot on his neck. Concerned that the problem was “ringworm,” the boy’s grandfather took him to the primary care provider, who prescribed nystatin cream. This produced modest improvement in the appearance of the lesion but had no effect on the associated itching. At that point, they were referred to dermatology for further evaluation.

The patient denies any other skin problems. The only animal he has been exposed to is his own dog, who has been part of the household for years. The boy is not involved in contact sports (eg, football, wrestling), and he reports that none of his siblings or friends have any skin complaints.

He is otherwise healthy and does not take any prescription medications.

EXAMINATION
The “rash” consists of a single, 2-cm lesion on the patient’s anterolateral neck. It is perfectly round and slightly erythematous, with a cleared center and scaly advancing margin. Palpable adenopathy is evident just above the lesion. There are no other lesions elsewhere, and the patient’s skin is otherwise unremarkable.

What is the diagnosis?

DISCUSSION
A KOH prep revealed abundant fungal elements, confirming the diagnosis of tinea corporis. This conclusion had already been reached empirically by the primary care provider, who chose nystatin cream for treatment. When that drug faltered, diagnostic doubt reared its head. The KOH settled the question once and for all—a crucial step, since nystatin is often prescribed for conditions that have no likelihood of responding to it (eg, eczema, psoriasis, granuloma annulare).

Nystatin, a polyene antifungal, was discovered and brought to market in 1950—that’s nearly 66 years ago! At that time, very few antifungal agents were available, so nystatin gained instant acceptance practically overnight. Since then, although dozens of newer and better antifungals have come on the market, nystatin continues to be prescribed out of sheer habit. A lot of water has gone down the river since 1950!

Nystatin was first isolated and developed by two scientists (Brown and Fuller) who worked in the lab at the New York State Health Department in the ’40s and ’50s. A popular practice at the time was to collect soil samples from local farmers to see what bacteria could be isolated. Brown and Fuller found a unique species of Streptomyces that they named S noursei after the dairy farmer whose soil they sampled.

They noted that this organism exuded a substance that inhibited yeast, mold, and fungi in vitro; when this substance was isolated and purified, it worked topically as well. They named this substance nystatin in honor of their employer, the New York State Health Department.

As charming as this history is, in the intervening 60+ years, better antifungals have been introduced and organisms have become less responsive to nystatin. In my opinion, except for unusual selective instances, there is no reason to prescribe nystatin instead of imidazole and allylamine (eg, miconazole, terbinafine, or naftifine).

For this patient, I prescribed oxiconazole lotion for twice-daily application to this small and limited lesion. With more extensive disease, I might add an oral antifungal, such as terbinafine. The patient’s lesion should resolve in two weeks or less.

One final note: In dermatology, we discourage the use of the term ringworm because it contributes to the “ick” factor associated with “worms”—which are not even involved in tinea corporis.

TAKE-HOME LEARNING POINTS
• Nystatin is a 66-year-old relic that has no place in treating ordinary dermatophytosis.

• “Newer” antifungals are more effective and kill a wider range of organisms, including yeast and fungi.

• In my experience, most nystatin is prescribed for conditions that have no chance of responding to it (eg, eczema, psoriasis, or granuloma annulare), because a differential was not considered.

• Primary care offices that are comfortable doing wet preps for clue cells and trichomonas feel no such need to perform KOHs to confirm fungal infection, and so diagnostic confusion results.

• There is no medical entity called ringworm. This is lay terminology based on the misbelief that worms are somehow involved in tinea.