Case of the Month

What is on this woman's neck?

What's Your Diagnosis?

Diagnosis: Nevus Simplex
(Seen in 64.4% of all patients, see details below)

A Casual Observation on the Prevalence of Nevus Simplex in Patients Seen in a Dermatology Clinic Charles E. Crutchfield, III, M.D. and Jeramiah Fairbanks, D.O.

Much has been written about the presence of nevi simplex in children. A resident physician (Jeramiah Fairbanks, D.O.)was rotating with me, and on day 1 of his rotation, we saw a patient with a nevus simplex on the nape of his neck. He asked me how common they were. I said: "Common, but I don't know any exact numbers, so let's count them over your 3-week rotation." He readily agreed, and so our casual observation began.

Methods

For the next three weeks, we asked every patient in the clinic if the resident could take a look at their neck to document if they had a harmless birthmark called a nevus simplex. Every patient agreed. One patient, age 92, was absolutely tickled to find out that she had such a birthmark, and she laughed her way out of the office, commenting, "At age 92, it's not every day you learn something new about yourself!"

Results
Full Population
N = 270
Present = 174 (64.4%)
Not Present = 96 (35.6%)
Presence by age
0-15: 53.3% (N=30)
16-30: 64.7% (N=68)
31-45: 60.0% (N=70)
46-60: 76.0% (N=50)
61-75: 69.4% (N=36)
>75: 56.3% (N=16)
Presence by Sex:
Males: 47.6% (N=84)
Females: 72.0% (N=186)
Presence by Race:
African American: 54.8% (N=62)
Asian: 61.5% (N=13)
Caucasian: 69.0% (N=184)
Hispanic: 42.9% (N=7)
Not Specified: 50.0% (N=4)

Comments

There seems to be a slight confusion on the exact name of these lesions. Terms used include stork bite, angel kiss, nevus flammeus, port-wine stain, and others. A 2010 JAAD article does a nice job at discussing and clarifying the terms. The lesion on the nape of the neck is a nevus simplex (a.k.a. stork bite), and the analogous mark on the glabella is called an angel kiss. These lesions are entirely different than a port wine stain (a.k.a. nevus flammeus). For a detailed explanation, please see:

Nevus simplex: a reconsideration of nomenclature, sites of involvement, and disease associations https://pubmed.ncbi.nlm.nih.gov/20728246/