June 2001

An 8-year-old boy is seen in the neuromuscular clinic for routine evaluation and update of his familial spastic paraparesis syndrome. It is noted that he has multiple (35-40) tan-colored spots on his skin with a generalized distribution, and his parents want to know what they are. They were first noted when he was an infant. Except for occasional itching, they are asymptomatic. They do not change in number, size, shape or location. However, their color occasionally changes from tan to a more erythematous hue when rubbed, scratched, or sometimes, for no apparent reason.

His past medical history is otherwise complicated with a form of familial spastic paraplegia noted above. His older sister has the same neurologic condition, but no other family member has these skin lesions. The skin lesions were first noted during infancy. His history is otherwise unremarkable. He is on no medications, has had no travel out of central Texas and the only animal exposure is to healthy domestic pets. His review of systems is also unremarkable except for the above. His immunizations are up to date.

Examination reveals normal vital signs and the cutaneous lesions noted above and seen in figures 1-6. Aside from his neurologic deficit, his exam was otherwise unremarkable.

What’s Your Diagnosis?

1. Pityriasis lichenoides et varioliformis acuta (PLEVA)
2. Urticaria pigmentosa
3. Erythema multiforme
4. Henoch-Schönlein purpura
5. Tinea corporis

Answer

The answer in this case is urticaria pigmentosa, which can have its onset from the neonatal period to adulthood. There are enough hints in the history to essentially rule out the other choices. This condition has nothing to do with any infectious disease, but we are often consulted for help with the diagnosis before the dermatologist. Descriptions of this unusual condition can be found in almost any dermatology text. My personal favorites are any publications by William L. Weston, MD, who is professor and chairman of the department of dermatology and professor of pediatrics at the University of Colorado Health Sciences Center in Denver. I still frequently refer to my copy of his first edition of Practical Pediatric Dermatology that I used in the late 1970s when I was a resident doing a dermatology elective with Dr. Weston. His emphasis has always been on the accurate description of the subject condition, rather than using color pictures. However, his most recent work, Color Textbook of Pediatric Dermatology, second edition, jointly written by Alfred T. Lane, MD, of Stanford and Joseph G. Morelli, MD, also of Denver, combines the best of both, excellent descriptions and color photographs. I strongly recommend this book for any practitioner who sees children.

Urticaria pigmentosa

Urticaria pigmentosa is a form of mastocytosis, which is a condition marked by an increased concentration of mast cells in various tissues. This usually occurs in the skin; however, the various organ systems can also be affected with variable expression of the condition. The symptoms revolve around the degranulation of the mast cell and release of histamine and other chemical mediators with certain stimulants; either physical (rubbing) or chemical (medications). In fact, rubbing one of these lesions will result in an urticarial response with erythema (Darier’s sign) as shown in figures 6-8. As the child ages, this sign often fades. With typical manifestations such as this, skin biopsy is usually not needed for the diagnosis. Sometimes the patient may have bullous lesions with this stimulation, but usually, one just sees the wheal and flare seen here. When other organ systems are involved, the manifestations can obviously be varied. Systemic mastocytosis may result in gastrointestinal upset, headache, dizziness, generalized itching, hives, flushing, etc. These reactions may follow the use of certain medications that stimulate the degranulation process, such as aspirin, alcohol, codeine containing products, anesthetic agents, etc. Treatment is with antihistamines, such as hydroxyzine or cyproheptadine. For refractory or unusual cases, I refer to one of the previous references or to a dermatologist when these choices do not work.

PLEVA

PLEVA is an unusual condition resulting in recurrent crops of erythematous papules that seem to ulcerate and form a crust (figures 9-12), much like varicella. In fact, the cases I have seen were initially referred to my infectious diseases clinic because of “recurrent or persistent varicella.” This will tend to persist for up to a year. Usually, no treatment is necessary unless the lesion(s) become secondarily infected. A lot of reassurance is usually all that is needed. You may see this referred to as “Mucha-Habermann” disease in some references, after the Austrian dermatologist Viktor Mucha and the German dermatologist Rudolf Habermann, both from the late 19th to the early 20th century. Referring to the 20th century in the past tense just now caused an acute psychotic reaction. I’ll have to continue this later.

OK, I’m back. The term “erythema multiforme” is used to describe a cutaneous condition that results in fixed lesions that are typically round or oval in shape. There may appear a central dusky or bluish-pale area resembling a target. Some experts subdivide erythema multiforme (EM) into EM minor (0-1 mucous membrane involvement) or EM major (2 or more mucous membranes involved). This diagnosis is often given to patients who actually have urticaria because of the similar ring forms it can take, along with a pale center (figure 13). One of the key differentiating features is the transient nature of urticaria, with individual lesions usually lasting less than 24 hours. EM often has no apparent cause, but it is known to be caused by herpes simplex, mycoplasma, various drugs, etc. The treatment is supportive.

Henoch-Schönlein purpura

Henoch-Schönlein purpura (HSP) is a form of vasculitis characterized by purpuric maculopapular lesions of the skin (palpable purpura), mostly on the buttocks and lower extremities (figures 14-16), gastrointestinal symptoms and renal abnormalities (hematuria). There may also be neurologic symptoms and joint pains with HSP. It appears to be due to immune complex formation, triggered by a variety of infectious diseases. The therapy is to treat the underlying cause if known, and support. Severe cases are often treated with steroids, and rarely, plasmapheresis. But don’t ask my opinion about plasmapheresis. I’m sure if I was desperately ill with some sort of immune complex disease, and this procedure was offered, I would try it, but in my mind, it is about as close to modern-day bloodletting as it gets. Of course, it is very difficult to conduct large-scale, double blinded, placebo-controlled trials on conditions that are fairly uncommon, such as those treated with plasmapheresis. The best available data can be reviewed on the NIH Web site, which reviews the clinical experience supporting its use in certain neurologic conditions. On second thought, maybe the medieval barbers were onto something.

Tinea corporis

Tinea corporis is a cutaneous fungal infection, usually caused by the various Microsporum or Trichophyton species. In many cases, as the infection progresses, there is central clearing with a ring-like appearance (ringworm) as dramatically shown in figure 17 (courtesy of Jim Bass, MD). This picture was taken on one of the lanais adjacent to the pediatric clinic at the old Tripler Army Medical Center in Honolulu. The blue color over the patient’s shoulder is the Pacific Ocean; not a bad place to train.

Finally, of historic interest, the term urticaria is derived from plants of the family Urticaceae, genus Urtica, commonly referred to as Nettle plants. These plants have stinging hairs projecting from the stems and leaves. Also of interest is the fact that urticaria pigmentosa is known as Nettleship disease after the London dermatologist and ophthalmologist Edward Nettleship (1845-1913) who described the condition in 1869. In Texas, a common nettle plant is the dreaded “Bull Nettle,” seen in figures 18-20. While its flower is pretty, its bite is painful as I have discovered many times. Also noted in the picture is the Texas state flower, the Blue Bonnet. It is actually against the law in Texas to pick these wildflowers. Between the Texas Rangers, rattlesnakes and bull nettle to protect them, the Blue Bonnets continue to thrive.

For your information:

• James H. Brien, DO, Pediatric Infectious Disease, Scott and White's Children's Health Center and Texas A&M University, College of Medicine, Temple, Texas. E-mail: jhbriend@aol.com