Girl develops itching scalp, white material in hair
What’s your diagnosis?
Click Here to Manage Email Alerts
A healthy 7-year-old girl is sent to the school nurse by her teacher, who was concerned about the girl scratching her scalp and seeing white material in her hair.
The nurse called the parent to pick up the child so she could be seen by her primary care provider, which was necessary before she could return to school. At the PCP’s office, white debris is seen on the girl’s hair. Therefore, a hair is removed and examined under the microscope, revealing something that appeared to be attached to the hair shaft, as shown in Figures 1 and 2.
What’s your diagnosis?
A. Eutrombicula alfreddugesi
B. Pediculus humanus capitis
C. Sarcoptes scabiei var. hominis
D. Piedraia hortae
Answer and discussion:
This would have been too easy if I used the common names rather than the genus and species. The answer is B, Pediculus humanus capitis, or the head louse, a common infestation in children and adults. Diagnosis is almost always made visually by either seeing the louse itself crawling around on the scalp or by seeing the egg on a hair shaft under low magnification, which may be an empty shell, as seen in Figure 1, or contain a nymph, as shown in Figure 2. Oftentimes the nymph can be seen to move inside the egg if it is not already dead. Treatment is usually with a topical pyrethroid, as noted in a recent issue of Pediatrics. The associated steps to take are also outlined in the report.
There are some “nit” lookalikes, such as seborrheic dermatitis, dandruff and white piedra, which is caused by yeast cells of a fungus belonging to the genus Trichosporon that attach to the hair shaft at the scalp, resulting in a fixed white lesion that appears at various locations on the hair shaft, as the hair grows out. White Piedra is pictured in Figure 3.
Piedra hortae translates into black stone. Piedraia hortae is the genus and species of the fungus that causes the dark nodular lesions of black piedra on the hair shaft (Figure 4), similar to white piedra, only caused by a darker fungus.
Dandruff and seborrheic dermatitis are on the same spectrum of scalp disorders, with dandruff being a much less inflammatory condition. Dandruff most commonly begins around puberty but can occur earlier. Younger children are more likely to have common inflammatory seborrheic dermatitis, causing similar flaking (Figure 5). In either case, they usually respond well to one of the topical medicated shampoos containing selenium sulfide or ketoconazole.
Eutrombicula alfreddugesi is the chigger mite. Like the scabies mite, the chigger mite requires mammalian blood, but unlike the scabies mite, the chigger does not burrow into the skin. They take a blood meal and get off, leaving behind a very pruritic bump. They are often called mower’s mites because they get on the uncovered legs of people mowing chigger-infested grass or weeds (Figure 6).
In children, particularly in boys, they tend to make their way to the groin area, often biting about the phallus, resulting in significant but relatively harmless swelling (Figure 7). These patients are often catheterized in urgent care out of concern for urinary obstruction. However, I have never seen or heard of an obstruction due to this condition or know anyone who has. The swelling is temporary and very soft, through which voiding comes easy.
The scabies mite (Sarcoptes scabiei var. hominis) bites all skin areas, but in children, their bites can be in a generalized distribution, seen as papulopustular lesions (Figure 8).
In infants, it is common to see these papulopustular lesions on the palms and soles.
Scabies should always be considered when evaluating lesions like these (Figures 9 and 10).
Parents will often have simple, nonpustular pruritic lesions on their hands between the fingers (Figure 11).
To manage the condition, I would recommend the current Red Book, pages 663-665. Nelson’s Pediatric Antimicrobial Therapy (The Yellow Book) is also an excellent quick reference. Both books recommend about the same thing; topical permethrin remains the mainstay of therapy, with oral ivermectin being helpful in older children with certain, difficult cases.
Columnist comments:
Lions, tigers and bears, oh my. The threats that Dorothy Gale and her companions had to face along their path to the land of Oz seemed insurmountable. However, taking one step at a time, the yellow brick road led them to their destination, and the rest (as they say) is history.
While we will not be facing lions, tigers or bears, by the time you are reading this we will be well into the fall and facing a trio of viral hazards (new strains of influenza, the COVID-19 variant BA.2.86 and respiratory syncytial virus). Therefore, for the first time, the new seasonal immunization recommendations for you, me and our patients will be different. The new influenza vaccine will again be a quadrivalent formulation (two type A strains and two type B strains), with a new A strain, but otherwise the same as last year. This year, we’ll have a new COVID-19 booster and the first effective RSV immunization. Until now, finding an RSV vaccine has been elusive. In the 1960s, a killed-virus RSV vaccine was developed but unfortunately failed in spectacular fashion, with recipients not only being unprotected but having worse RSV disease upon exposure than the unvaccinated. This was due to something called the antibody-dependent enhancement effect. If you are interested, an article in Scientific American looked at the history of RSV vaccine development. RSV immunization is available for adults aged older than 60 years, pregnant women and children at high risk for RSV disease. Check with the AAP and CDC guidelines for current recommendations.
Please keep in touch. – JB
References:
American Academy of Pediatrics. Committee on Infectious Diseases. Red Book. Report of the Committee on Infectious Diseases. Academy of Pediatrics; 2021. https://redbook.solutions.aap.org/redbook.aspx. Accessed Oct. 4, 2023.
Bradley JS, Nelson JS, eds. Nelson’s Pediatric Antimicrobial Therapy. 29th ed. American Academy of Pediatrics;2023:663-665.
Haelle T. Scientific American. RSV vaccines are finally here after decades of false starts. https://www.scientificamerican.com/article/rsv-vaccines-are-finally-here-after-decades-of-false-starts. Published March 20, 2023. Accessed Oct. 4, 2023.
Nolt D, et al. Pediatrics. 2022;doi:10.1542/peds.2022-059282.
For more information:
Brien is a member of the Healio Pediatrics Peer Perspective Board and an adjunct professor of pediatric infectious diseases at McLane Children's Hospital, Baylor Scott & White Health, in Temple, Texas. He can be reached at jhbrien@aol.com.
Collapse
Click Here to Manage Email Alerts