An Enlarging Nodule, Itchy Bumps, and a Scaling Lesion

A blue-black nodule has been present next to a 19-year-old woman's left eye since birth. After recent accidental trauma, the lesion has enlarged.

What does this look like to you?

A. Nevus of Ota.
B. Cellular blue nevus.
C. Combined nevus.
D. Spitz nevus.
E. Melanoma.

Which of the following statements is true of this lesion?

F. It appears more commonly on a buttock.
G. It is more common in women.
H. It most commonly appears at birth or at about age 40 years.
I. It can invade the skull.
J. It is associated with endocrine overactivity.

Bonus question: Why does this pigmented lesion appear grayish blue-black rather than brown or black?

Answer: The biopsy confirmed a benign cellular blue nevus, B. These nevi are evenly colored gray, bluish, or black and have symmetric, smooth borders. Congenital or acquired, single or multiple blue nevi can arise at any location. Statements F, G, H, and I characterize these lesions. Although they are benign, these congenital lesions occasionally can be invasive. Increased endocrine activity is not associated with these nevi. A nevus of Ota is a gray or bluish macule that involves the eye. Combined nevi generally possess features of blue nevi and of compound nevi, with one of the lesions layered atop the other. These usually thicker nevi are typically darker brown to black, symmetric, and have smooth borders; they can be found anywhere on the body. Spitz nevi usually are pink, brownish red, or purplish red lesions of less than 10 mm. Melanoma is always a concern; this patient’s nevus resembled a nodular variant of skin cancer. The biopsy ruled out a malignancy.

Answer to the bonus question: The grayish blue-black color is attributed to bending light rays; dermal melanin from dermal melanocytes is brown on the surface of the skin but appears to be gray or blue when below the surface.

An 11-year-old boy has had “itchy bumps” on the sides of his fingers for 1 week. The vesicles arose after the patient had been on a roller coaster.

Which of the following do you suspect?
A. Pompholyx.
B. Tinea manuum.
C. Scabies.
D. Contact dermatitis.

Bonus question: Which are potential aggravating factors for this patient's disorder?

A. Tinea pedis.
B. Nickel allergy.
C. Female sex.
D. Atopic dermatitis.
E. Hyperhidrosis.

Answer: Pompholyx, A—which means bubble and is also known as dyshidrosis— is characterized by pruritic vesicles on the sides of the fingers and hands. Stress induced by fear of the roller coaster ride is thought to have precipitated this patient’s disorder.¹ It is more common for a contact dermatitis to erupt on exposed areas—rather than the sides—of the fingers. Scabies is intensely pruritic and more widespread than the eruption in this patient, and it features few intact vesicles. Tinea manuum—a dermatophyte infection of the hand— generally develops more slowly than this patient’s rash and is more scaly than vesicular. Answer to the bonus question: In addition to stress, tinea pedis, A, and nickel sensitivity, B, are aggravating factors for pompholyx. Atopy may be a risk factor, although the relationship has not been firmly established. Neither hyperhidrosis nor the patient’s gender is associated with the disease.

An asymptomatic, circular, scaling lesion on the trunk of a 42-year-old man consistently reappears after clearing. The lesion initially erupted 3 months earlier; since then, it has arisen, lasted a few weeks, and disappeared several times. The patient has no other complaints; he takes no medications.

Your differential includes . . .

A. Tinea corporis.
B. Tinea versicolor.
C. Granuloma annulare.
D. Erythema annulare centrifugum.
E. Lupus erythematosus.

What do you include in your initial workup?
F. A bacterial culture.
G. A test for antinuclear antibodies.
H. A potassium hydroxide( examination.
I. Measurement of fasting plasma glucose levels.

Answer: The presentation strongly suggested erythema annulare centrifugum, D, a reactive process to an underlying disease that is often undiagnosed. Tinea corporis, tinea versicolor, and granuloma annulare lesions do not wax and wane as did this patient’s eruption. The rash of lupus erythematosus also tends to persist and typically arises on sunexposed skin. Perform a potassium hydroxide examination, H, for a dermatophyte infection, which is the most common underlying disorder; this patient had tinea pedis. Further workup is needed only if the patient has symptoms other than the rash. Treatment of the tinea pedis resulted in resolution of the infection and the erythema annulare centrifugum as well.

A persistent, pruritic plaque on one shin has bothered a 75-year-old man for 5 years. Over-the-counter preparations have not resolved the lesion.

Do you recognize this eruption?
A. Stasis dermatitis.
B. A dermatophyte infection.
C. Impetigo with cellulitis.
D. A Candida infection.
E. Lichen simplex chronicus.

You prescribe which of the following?
F. A corticosteroid cream.
G. An antifungal cream.
H. An oral antibacterial agent.
I. An oral antifungal agent.
J. Occlusive dressings.

Answer: This excoriated plaque is lichen simplex chronicus, E, which is often referred to as “the itch that rashes.” This self-inflicted dermatosis is frequently triggered by a precipitating factor. To confirm the diagnosis, occlude the lesion so that the patient has no access to the area and examine it 1 or 2 weeks later. Invariably, significant healing will have occurred because the lesion was not rubbed or scratched. Occasionally, particularly in patients with long-standing disease, it is not possible to identify the inciting cause of the chronic itch/scratch cycle. However, it is reasonable to search for underlying chronic disease, such as venous insufficiency, myxedema, or xerosis. Tailor treatment to the inciting disorder. This patient had long-standing xerosis; a corticosteroid cream, F, and occlusive dressings, J, ameliorated the pruritic skin condition.