Go 'under cover' to get to the bottom of painful diaper rash

The physician must carefully consider the variety of causes of diaper rash before making a diagnosis.

SAN FRANCISCO — An effective evaluation of diaper rash relies on the willingness of the pediatrician to look beyond the obvious, said Susan Boiko, MD, here at the annual meeting of the American Academy of Dermatology.

"Keep in mind that the diaper area can be affected by the same cutaneous and subcutaneous conditions as any part of the body," said Boiko, a consultant in pediatric dermatology at the Skin Sciences Institute, Children's Hospital Medical Center in Cincinnati. "Be a detective. Ask about the patient's medical history and remove all of the patient's clothing for a complete cutaneous examination."

The myriad causes of diaper rash range from relatively mundane seborrheic dermatitis to Kawasaki syndrome, with just about everything in between including viral vesicobullous infection, bullous impetigo due to Staphylococcus aureus congenital syphilis, HIV infection, scabies, psoriasis, Langerhans' cell histiocytosis and acrodermatitis enteropathica (AE).

"Make sure you know what your patient's caregiver has been applying to the area, even to the point of asking them to bring all of the products and medications in a shopping bag," said Boiko. "Carefully inspect the diapering system to see if the diaper is contributing to the rash, and educate the caregiver about preventative and therapeutic options."

All patients deserve a careful cutaneous evaluation with good lighting and magnification, Boiko stressed. "If the diagnosis is not certain," said Boiko, "a complete skin examination, including intertriginous areas, scalp and mucous membranes may be helpful in focusing on a diagnosis." Ancillary tests such as skin scrapings for microscopic examination and culture and skin biopsies can be used when a diagnosis is uncertain.

Systemic illnesses

Well demarcated tender red patches are a hallmark of staphylococcal scalded skin syndrome.

Flaccid, easily ruptured blisters in the diaper area, especially coupled with a recent circumcision, and inflammation around the umbilicus or foul odor should trigger a complete physical examination, Boiko said. "Sometimes the bulla ruptures," Boiko pointed out, "leaving a collarette of scale, a rim of postinflammatory hyperpigmentation and a central red, raw area of exposed, weeping dermis that may appear burn-like."

Bullae can be cultured, and a Gram's stain of pus can immediately be checked for gram-positive bacteria characteristic of S. aureus To differentiate a bacterial or viral vesico-bullous infection from a noninfectious inherited bullous disease, a frozen section of the blister roof or a skin biopsy for pathology and immunofluorescence may be helpful, Boiko said.

Bullous impetigo due to S. aureus in an infant younger than 1 month of age should be reported to the director of the newborn nursery where the child stayed after birth, especially if the child was circumcised. The circumcision site and cord stump or umbilicus should also be cultured for Staphylococcus.

Hospitalization for parental anti-staphylococcal therapy may be warranted, she said. Staphylococcal scalded skin syndrome (SSSS) may selectively involve the diaper area. Well-demarcated tender red patches, sometimes with superficial, easily ruptured vesicles and bullae are a hallmark of SSSS. Because the dermis is uncovered, involved skin needs the same treatment as a second degree burn: maintenance of hydration and nutrition, protection of the dermis with meticulous wound care and tetanus prophylaxis. Additionally, systemic anti-staphylococcal drugs are needed to treat the underlying infection.

Staph infection may cause purulent conjunctivitis, otitis media and/or meningitis, so temperature, a medical history and physical examination are essential for diagnosis.

Scarlet fever due to systemic Streptococcus pyogenes infection characteristically shows an accentuation of a scarlatiniform rash in the groin area, Boiko said.

Kawasaki syndrome, sometimes associated with strep infection, can also show diaper area erythema and desquamation within the first week of symptoms. "Kawasaki syndrome should be considered in an infant or young child with persistent fever, lymphadenopathy, mucosal and conjunctival erythema and edema and desquamating erythema in the diaper area. Early treatment may prevent development of coronary artery disease, Boiko said.

Perianal streptococcal cellulitis, with chronic anal and perianal erythema and edema, may require prolonged antibiotic therapy to be eradicated.

Boiko reported that congenital syphilis is on the rise. "Any newborn with moist red perianal papules and plaques and/or blisters and erosions on the palms and/or soles, may not only have congenital syphilis, but also should be evaluated for concomitant HIV infection," Boiko said. "HIV infection should be in the differential diagnosis of any diaper rash that is chronic and progressive."

The virus itself does not cause a rash, but associated immunosuppression contributes to rash persistence and resistance to conventional therapy.

Other fungi

Candida is not the only fungus that may affect the diaper area. Epidermophyton floccosum and other dermatophyte fungi can also appear in the diaper area, Boiko said. A potassium hydroxide (KOH) preparation, coupled with a fungal culture, will aid in the diagnosis, while treatment with topical antifungals is usually sufficient.

Varicella zoster virus can appear as chickenpox or herpes zoster. A barrier cream or ointment may be used in the diaper to protect eroded skin. Cytomegalovirus may be found in diaper area ulcerations of immunosuppressed infants.

Scabies are commonly found in the groins of infants and children. The penis, umbilicus and palmar creases are good places to look for characteristic linear burrows. "A burrow scraping with a drop of mineral oil and a coverslip may reveal the mite, ova or mite feces — clinching the diagnosis," Boiko said. The patient should be treated with a topical scabicide, such as permethrin 5% cream. It is also strongly recommended that all people who have direct skin contact with the patient be treated as well.

Wiskott-Aldrich syndrome (WAS) is a rare, autosomal recessive genetic defect, which affects only males. The classic triad of WAS includes atopic or seborrheic dermatitis, thrombocytopenia and recurrent purulent infections. "Look for petechiae in the patches of the dermatitis and ask about recurrent purulent infections in an infant boy with unresolving atopic or seborrheic dermatitis," Boiko said.

Seborrheic dermatitis has an erythematous scaly, greasy, appearance and may occur in the scalp, postauricular skin, intertriginous folds and groin. Especially when there is moisture it may be secondarily colonized with Candida resulting in satellite papules and pustules. Langerhans' cell histiocytosis, graft vs. host disease and rare metabolic disorders should be considered if rapid resolution of seborrheic dermatitis with low-potency topical steroids does not occur.

Langerhans' cell histiocytosis may be present at birth or may arise during infancy. Red-purple papules on skin or persistent diaper rash coupled with prolonged cradle cap and chronic otitis media should arouse suspicion. Biopsy of a papule will yield the diagnosis and referral to a pediatric oncologist is recommended.

AE due to a variety of causes may present with a severe diaper rash and a perioral eruption. AE is usually secondary to zinc deficiency, Boiko pointed out. Although it is often secondarily infected with Candida, the rash will not resolve until the underlying cause is diagnosed and treated. – by Rochelle Nataloni

For more information:

Boiko S. The bottom line on diapers and diaper rashes. Presented at the American Academy of Dermatology meeting. March 21-26. San Francisco.

Boiko S. Diapers and diaper rash. Dermatology Nursing 1997;9:33-70.