Multiple minute digitate hyperkeratosis, also known as digitate keratoses, disseminated spiked hyperkeratosis, familial disseminated piliform hyperkeratosis, and minute aggregate keratosis is a rare cutaneous condition, with about half of cases being familial, inherited in an autosomal dominant fashion, while the other half are sporadic.^[1]

Signs and symptoms

Multiple minute digitate hyperkeratosis is mostly a nonfollicular digitate keratosis that affects the limbs and trunk. There is no impact on the face or palmoplantar surfaces. The lesions consist of skin-colored, yellow, brown, or white spicules that range in length from 0.5 to 5.0 mm and diameter from 0.3 to 3.0 mm. Occasionally, flat-topped, dome-shaped, or crateriform papules are also present.^[2]

Causes

Multiple minute digitate hyperkeratosis may be sporadic or familial.^[2]

Diagnosis

Histopathology reveals a stratum granulosum with varying thickness and localized orthokeratotic hyperkeratosis originating from a tented epidermis. Rarely, there have also been reports of superficial cutaneous lymphoplasmocytic infiltrates, parakeratosis, and epidermal invagination. A recurring characteristic that unites all of the cases that have been documented is the absence of follicular involvement.^[3]

Reduced keratohyaline granules with varying numbers of Odland bodies are seen under electron microscopy.^[3]

Treatment

While improvements with various topical keratolytics and topical and oral retinoids have been reported, treatment is frequently ineffective or only temporary.^[2]