Q: On the basis of the skin findings, which test should be ordered to establish a diagnosis?
- Biopsy of the lesions
- Hemoglobin A1C
- Fungal culture
- Brush with soap and water or alcohol
- Bacterial culture
A: Patchy brown, waxy scales in a patient who neglects normal cleansing should raise the possibility of dermatosis neglecta. Hence, brushing with soap and water or alcohol is the correct answer.
In this patient, the plaques were easily removed using an alcohol-soaked swab, revealing underlying normal skin with bleeding spots. The patient’s family was instructed to lightly scrub the area daily with a washcloth, soap, and water. The lesions resolved completely over the next 3 weeks.
Dermatosis neglecta is a condition that results from the accumulation in the epidermal stratum corium of sebum, sweat, corneocytes, and bacterias in areas of unwashed skin. It affects all age groups, and it has a similar prevalence in both sexes. Sometimes, an underlying physical disability or emotional problem is the cause, other times it is due to prior trauma or hyperesthesia of the affected area. Dermatosis neglecta presents with asymptomatic areas of dark brown patches or plaque with cornflake-like scales and a verrucous surface.1–4 The diagnosis is usually easy and is based on the characteristic findings and the simple test described above. For treatment, in some cases a keratolytic lotion containing lactic acid, glycolic acid, urea, or salicylic acid is helpful.4
MISDIAGNOSIS IS EASY
Dermatosis neglecta could easily be misdiagnosed as verrucous epidermal nevus, terra firma-forme dermatosis, acanthosis nigricans, or another less common dermatosis of “dirty skin” lesions, such as confluent and reticulate papillomatosis (Gougerot-Carteaud syndrome).2–4
Verrucous epidermal nevus appears at birth or early childhood. Patients have verrucous papules and plaques that commonly follow a narrow linear distribution.
Acanthosis nigricans is characterized by broad, velvety, hyperpigmented smooth plaques on the neck, axillae, and flexures. It is related to insulin resistance, obesity, and underlying malignancy.
Confluent and reticulate papillomatosis is a rare dermatosis of unknown cause, with a pigmented reticular pattern distributed on the central trunk. Patients tend to practice normal hygiene.
Terra firma-forme dermatosis is characterized by dirt-like patches that are resistant to usual hygiene measures but that can be eliminated by rubbing with isopropyl alcohol. The cause is unknown, and it is not related to a lack of cleansing. It is considered a variant of dermatosis neglecta.
The medical literature contains few reports of dermatosis neglecta, but the true incidence is probably underestimated. Early recognition by a physician avoids the need for aggressive diagnostic and therapeutic procedures.