Seasonal dermatoses: What to look for

A change in the calendar often ushers in a wave of similar dermatologic cases. Take this test to see if you are up to speed on seasonal skin problems.

For clinicians, the time of year isn’t marked only by the weather or holidays or family gatherings. No, we also mark the time of year by the type of patient and problem we’re likely to see. For example, to a clinician, the Fourth of July means trauma patients, Thanksgiving means MI, and winter means psoriasis flares. This time of year, as people spend more time outdoors, certain dermatoses will present. Here are common seasonal afflictions you’re bound to see, if you haven’t already.


FIGURE 1. Pink plaque seen on the dorsal hand after a pool party

Case 1

Presentation
A 30-year-old physician has a unilateral rash on his right dorsal hand. The two-day-old eruption (Figure 1) is painful and slightly pruritic. Although the patient lives in a wooded area and often works outside, he was busy this weekend having a pool party to celebrate finishing his residency. No one else in the house has a similar rash. The patient has no history of skin disease.

What should you ask this patient?
a. Do you have any pets?
b. What did you drink at the party?
c. Does any member of your family get similar eruptions?
d. Have you had any tick bites?

Answer: b. What did you drink at the party?
This is a classic case of a phytophotodermatitis. The presentation of unilateral erythematous plaques and vesicles on the dorsal lateral hand in the setting of an outside party in the spring or summer months should prompt a line of questioning about margaritas, mojitos, and caipirinhas.

These springtime/summertime drinks all use limes. Limes contain furocoumarins, which produce a phototoxic skin reaction when exposed to sunlight. When the furocoumarin contacts the skin, it is harmless, but a photochemical reaction occurs with exposure to UV light, leading to the sunburnlike phytophotodermatitis. There will often be linear streaks where the lime juice has run down the skin, especially on the back of the hand used to crush the fruit. Phytophotodermatitides also occur with celery, parsnips, parsley, dill, carrot, and fig.1

Follow-up 1

Two weeks later, the patient has a similar eruption on his legs. During that period, he had taken his dog to the veterinarian and had no more parties. In fact, he spent the entire weekend in the yard cutting down tall grasses. However, he repeatedly insists there is no poison ivy in the area.

The best treatment for this condition is:
a. Oral prednisone taper
b Oral antifungals
c. Topical antifungals
d. Washing the skin and applying topical emollients

Answer: d. Washing the skin and applying emollients.
Another cause of phytophotodermatitis is common weeds (cow parsley, wild chervil) that come into contact with the skin as the patient uses a motorized trimmer.

Phytophotodermatitis is a nonimmunologic, phototoxic reaction usually associated with pain rather than pruritus. Treatment would consist of prompt washing with soap and water and application of emollients if lesions develop. Rarely are topical corticosteroids necessary, but consider them for severely edematous reactions.

Follow-up 2

When your patient returns after three weeks, he has a 2-cm area of discoloration on his right hand at the site of the initial lesion.

You should tell him
a. A punch biopsy is necessary to rule out melanoma.
b. Excisional biopsy is necessary to rule out melanoma.
c. The discoloration is likely to be permanent but is not worrisome.
d. The discoloration is not likely to be permanent.

Answer: d. The discoloration is not likely to be permanent.
Localized postinflammatory hyperpigmentation often develops several weeks after the initial plaques of phytophotodermatitis resolve. In most patients, this cause of dyschromia lasts weeks to months but usually resolves.

Case 2

Presentation

A 46-year-old shopkeeper presents to your office with a 20-day history of a worsening skin eruption (Figure 2). What began as a solitary bump on her hand has now increased in number and size. She cannot believe this is happening to her because all of her time in the past month has been spent tending to her beautiful rose garden. The patient was seen 15 days ago by a colleague, who took a skin biopsy for culture and placed the woman on itraconazole.


FIGURE 2. Multiplying and enlarging lesions on the hand of a pet lover

Your colleague likely believes the patient has what disease?
a. Sporotrichosis
b. Dermatophytosis
c. Histoplasmosis
d. Coccidioidomycosis
e. Cryptococcosis

Answer: a. Sporotrichosis.
Your colleague was quite right in thinking this looked like sporotrichosis. Moreover, when the patient identified herself as a rose gardener, sporotrichosis would likely have moved to the top of the list of differential diagnoses.

Follow-up 1
According to the patient, the itraconazole has not been effective, and the culture has been negative to date. She denies fever, chills, or night sweats. There has been no recent travel. Except for her many pets, which include a dog, cat, iguana, and fish, she lives alone. She has no other health problems and is on no additional medication.

Your next step should be:
a. Switch the patient to fluconazole, as the organism is likely resistant to itraconazole.
b. Ask the patient if there is poison ivy near her rose bushes.
c. Ask if she has cleaned her fish tank recently.
d. Ask if her dog or cat has any skin problems.
e. Call the health department to identify bacterial resistance patterns in the area.

Answer: c. Ask if she has cleaned her fish tank recently.
When the culture yielded no growth and there was no response to itraconazole, the diagnosis of sporotrichosis should have been re-evaluated. It is important for clinicians to remember that there is a differential diagnosis for a “sporotrichoid” pattern: pink to violaceous suppurative nodules or ulcers on the hands and arms that move proximally with lymphangitic spread.

The most common conditions causing a sporotrichoid pattern in an immunocompetent host are sporotrichosis, cutaneous nocardiasis, leishmaniasis, and infection with an atypical mycobacterium, namely Mycobacterium marinum. This patient’s presentation is classic for a fish tank granuloma, which occurs in both freshwater and saltwater environments. Diagnosis is confirmed with culture, but the laboratory must be told to look for the atypical mycobacterium. The organism enters the skin through sites of trauma. Exposure most commonly occurs while the patient is cleaning a fish tank.2

Follow-up 2
Once the causative organism of this skin eruption was confirmed by laboratory testing as M. marinum, antibiotic therapy could be started.

First-line therapy for an M. marinum infection is:
a. Cephalexin
b. Fluconazole
c. Minocycline
d. Acyclovir

Answer: c. Minocycline. Treatment includes rifampin, ethambutol, or minocycline. Patients should be treated for four to six weeks after resolution of symptoms. Some patients require up to 18 months of antibiotic treatment. If, after long-term antibiotic treatment, there is still no response, surgical excision is advised.

Case 3

Presentation
A 25-year-old African-American woman presents in April with 1- to 2-mm round red papules on her face, arms, and abdomen. In some areas, the papules are so numerous they form large plaques with scant scale. Other areas are unaffected.

The submental and retroauricular areas are noticeably spared. This is the second time the patient has had this eruption. Last year she visited Jamaica in November and developed a similar eruption, which resolved during her two-week vacation.

Which of the following tests would you order next?
a. Ro and La antibodies
b. Angiotensin-converting enzyme level
c. Erythrocyte sedimentation rate
d. Eosinophil count

Answer: a. Ro and La antibodies. When evaluating a photosensitivity disorder featuring red papules and plaques with some scaling on sun-exposed skin, consider subacute cutaneous lupus erythematosus (SCLE) in the differential diagnosis. SCLE can usually be differentiated clinically from other photosensitivity disorders because of its annular appearance and sparing of the mid-face; however, testing for Ro and La antibodies is sensitive (75%-90% and 30%-40%, respectively) for SCLE. SCLE can occasionally be drug-induced, most commonly due to hydrochlorothiazide.

Follow-up
Ro and La studies are negative, and porphyrin studies are normal. The patient takes no medications and does not apply anything topically to her skin.

Her presentation is most consistent with what condition?
a. Atopic dermatitis
b. Polymorphous light eruption
c. Tinea corporis
d. Systemic lupus erythematosus

Answer: b. Polymorphous light eruption (PMLE).
In temperate areas, up to 10%-20% of the population may have PMLE. It most often presents in the early spring but can also occur in late winter. However, when patients travel outside temperate areas, such as to the tropics, they can experience flares at anytime of year.

There is a “polymorphous” eruption on sun-exposed skin, and women are more commonly affected than men. The highest incidence occurs during the third or fourth decade of life, but patients at any age can be affected.3

Dr. Poligone is a research fellow in dermatology at Yale University School of Medicine, New Haven, Conn.

References

1. Bolognia JL, Jorizzo JL, Rapini RP, eds. Dermatology. St. Louis, Mo: Mosby; 2003:265-284.

2. Bartralot R, Garcia-Patos V, Sitjas D, et al. Clinical patterns of cutaneous nontuberculous mycobacterial infections. Br J Dermatol. 2005;152:727-734.

3. Fesq H, Ring J, Abeck D. Management of polymorphous light eruption: clinical course, pathogenesis, diagnosis and intervention. Am J Clin Dermatol. 2003;4:399-406.

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