Foot rash during self-treatment

The patient’s toenail thickening appeared consistent with possible onychomycosis—but in addition, there was a marked inflammatory and vesicular eruption consistent with an allergic contact dermatitis.

TTO, also known as melaleuca oil, is a popular product used to treat many disorders including alopecia, seborrheic dermatitis, and onychomycosis.¹ Unfortunately, it is a complex compound, and the rate of positive reactions to patch testing ranges from 0.1% to 3.5%.²

There are 2 types of contact dermatitis: irritant and allergic. Irritant contact dermatitis results from an irritating or relatively caustic substance causing direct damage and inflammation to the skin. In allergic contact dermatitis, as occurred here, there is sensitization to a substance that causes a type IV delayed cell-mediated immune response. Although radioallergosorbent blood testing will usually show immunoglobulin E antibodies to the inciting substance, patch testing is more specific and will show a reaction to the imputed substance on direct skin application. This usually is performed as a panel of antigens tested at the same time.

The mainstay of treatment is to identify, stop use of, and then avoid the sensitizing substance. Topical steroids (triamcinolone 0.1% ointment or clobetasol 0.05% ointment twice daily) are helpful in most cases. If the condition is severe or does not respond to initial therapy, systemic steroids (prednisone 40 mg/d for 5 days for most cases or a 2- to 3-week taper for Rhus dermatitis [eg, poison ivy]) are often effective.³

This patient was instructed to stop using TTO and counseled to avoid it in the future. She was told that her nails might fall off due to the inflammation, which might cure her onychomycosis, and that it takes 12 to 18 months to grow new toenails. She was advised to return for evaluation if the new nails developed any abnormalities or if her onychomycosis recurred. Oral terbinafine 250 mg/d for 90 days is usually a safe and effective therapy.

‌

Photo and text courtesy of Daniel Stulberg, MD, FAAFP, Professor and Chair, Department of Family and Community Medicine, Western Michigan University Homer Stryker, MD School of Medicine, Kalamazoo.

The patient’s toenail thickening appeared consistent with possible onychomycosis—but in addition, there was a marked inflammatory and vesicular eruption consistent with an allergic contact dermatitis.

TTO, also known as melaleuca oil, is a popular product used to treat many disorders including alopecia, seborrheic dermatitis, and onychomycosis.¹ Unfortunately, it is a complex compound, and the rate of positive reactions to patch testing ranges from 0.1% to 3.5%.²

There are 2 types of contact dermatitis: irritant and allergic. Irritant contact dermatitis results from an irritating or relatively caustic substance causing direct damage and inflammation to the skin. In allergic contact dermatitis, as occurred here, there is sensitization to a substance that causes a type IV delayed cell-mediated immune response. Although radioallergosorbent blood testing will usually show immunoglobulin E antibodies to the inciting substance, patch testing is more specific and will show a reaction to the imputed substance on direct skin application. This usually is performed as a panel of antigens tested at the same time.

The mainstay of treatment is to identify, stop use of, and then avoid the sensitizing substance. Topical steroids (triamcinolone 0.1% ointment or clobetasol 0.05% ointment twice daily) are helpful in most cases. If the condition is severe or does not respond to initial therapy, systemic steroids (prednisone 40 mg/d for 5 days for most cases or a 2- to 3-week taper for Rhus dermatitis [eg, poison ivy]) are often effective.³

This patient was instructed to stop using TTO and counseled to avoid it in the future. She was told that her nails might fall off due to the inflammation, which might cure her onychomycosis, and that it takes 12 to 18 months to grow new toenails. She was advised to return for evaluation if the new nails developed any abnormalities or if her onychomycosis recurred. Oral terbinafine 250 mg/d for 90 days is usually a safe and effective therapy.

‌

Photo and text courtesy of Daniel Stulberg, MD, FAAFP, Professor and Chair, Department of Family and Community Medicine, Western Michigan University Homer Stryker, MD School of Medicine, Kalamazoo.

The patient’s toenail thickening appeared consistent with possible onychomycosis—but in addition, there was a marked inflammatory and vesicular eruption consistent with an allergic contact dermatitis.

TTO, also known as melaleuca oil, is a popular product used to treat many disorders including alopecia, seborrheic dermatitis, and onychomycosis.¹ Unfortunately, it is a complex compound, and the rate of positive reactions to patch testing ranges from 0.1% to 3.5%.²

There are 2 types of contact dermatitis: irritant and allergic. Irritant contact dermatitis results from an irritating or relatively caustic substance causing direct damage and inflammation to the skin. In allergic contact dermatitis, as occurred here, there is sensitization to a substance that causes a type IV delayed cell-mediated immune response. Although radioallergosorbent blood testing will usually show immunoglobulin E antibodies to the inciting substance, patch testing is more specific and will show a reaction to the imputed substance on direct skin application. This usually is performed as a panel of antigens tested at the same time.

The mainstay of treatment is to identify, stop use of, and then avoid the sensitizing substance. Topical steroids (triamcinolone 0.1% ointment or clobetasol 0.05% ointment twice daily) are helpful in most cases. If the condition is severe or does not respond to initial therapy, systemic steroids (prednisone 40 mg/d for 5 days for most cases or a 2- to 3-week taper for Rhus dermatitis [eg, poison ivy]) are often effective.³

This patient was instructed to stop using TTO and counseled to avoid it in the future. She was told that her nails might fall off due to the inflammation, which might cure her onychomycosis, and that it takes 12 to 18 months to grow new toenails. She was advised to return for evaluation if the new nails developed any abnormalities or if her onychomycosis recurred. Oral terbinafine 250 mg/d for 90 days is usually a safe and effective therapy.

‌

Photo and text courtesy of Daniel Stulberg, MD, FAAFP, Professor and Chair, Department of Family and Community Medicine, Western Michigan University Homer Stryker, MD School of Medicine, Kalamazoo.