Lichen planus and other lichenoid dermatoses: Kids are not just little people

Lichenoid dermatoses, a group of inflammatory skin conditions with characteristic clinical and histopathologic findings, range from common to rare. Classic lichen planus typically presents as pruritic, polygonal, violaceous flat-topped papules and plaques; many variants in morphology and location also exist. Other lichenoid dermatoses share similar clinical presentations and histopathologic findings. These include lichenoid drug eruption, lichen planus-like keratosis, lichen striatus, lichen nitidus, and keratosis lichenoides chronica. Epidemiologic characteristics vary among each lichenoid disorder. While classic lichen planus is considered a disease of adults, other lichenoid dermatoses may be more common in younger populations. The literature contains an array of reports on the variations in presentation and successful management of lichen planus and lichenoid dermatoses among diverse populations. Familiarity with the characteristics of each lichenoid dermatosis, rare or common within each patient population, is key to accomplishing timely recognition and effective management.

Lichen nitidus with involvement of the palms

A 14-year-old girl presented with hyperkeratotic, pitted, skin-colored papules on a slightly erythematous surface on her palms and erythematous and squamous papules around her ankles. She was clinically and histopathologically diagnosed with lichen nitidus, which is observed rarely on the palms.

A case of palmar lichen nitidus presenting as a clinical feature of pompholyx

Lichen nitidus (LN) is an uncommon chronic eruption of an unknown cause, and it is characterized by tiny, discrete, flesh-colored papules. The sites of predilection are the genitalia, trunk and extremities. Unilateral palmar involvement with pruritus is infrequent. We report here on a case of LN confined to the right palm, and the patient presented with multiple, pruritic, erythematous to flesh-colored, tiny papules and vesicles that mimicked pompholyx. The histopathological examination of a skin biopsy specimen showed the typical findings of LN.

Generalized lichen nitidus with involvement of the palms following interferon alpha treatment

Lichen nitidus is an uncommon dermatosis of unknown etiology. Here we present the case of a generalized lichen nitidus with involvement of the palms in a patient with hepatitis C after systemic treatment with interferon alpha and ribavirin. Furthermore in our patient we could show a strong lesional expression of MxA, a protein specifically induced by type I interferon. It is tempting to speculate that interferon alpha may be involved in the pathogenesis of lichen nitidus.

Lichen nitidus palmoplantaire

BACKGROUND

Lichen nitidus is a rare condition, which may be a cause of palmoplantar hyperkeratosis. We report two cases.

CASE REPORTS

A 53 year-old woman presented with a dry and fissured palmoplantar hyperkeratosis. Histological examination of a biopsy showed the typical features of lichen nitidus. Significant improvement was obtained with acitretin. A few months later, multiple lichen nitidus papules appeared on the limbs and the abdomen. A 67 year-old woman was referred to us for a fissured, disabling palmoplantar hyperkeratosis refractory to topical steroids. Histological examination led to the diagnosis of lichen nitidus. Local PUVA therapy resulted in the cleaning of her lesions. Later, typical papules of lichen nitidus appeared on her elbows.

DISCUSSION

Nineteen cases of palmoplantar localization of lichen nitidus have been described. The features are usually tiny yellow papules but sometimes a non-specific keratoderma resembling chronic eczema. Palmoplantar involvement of lichen nitidus may be isolated or associated with cutaneous lesions on unusual sites. Oral retinoids and local PUVA are effective treatments.

Periappendageal lichen nitidus: report of a case

BACKGROUND

The histology of lichen nitidus has been described previously but a follicular variant has not been emphasized.

METHOD

We report a case of lichen nitidus with periappendageal inflammation resulting in histologic similarities to lichen striatus.

RESULTS

This case extends the spectrum of histologic findings in lichen nitidus and shows overlap in the distribution of the inflammatory infiltrate in lichen nitidus and lichen striatus.

Immunohistochemical examination of lichen nitidus suggests that it is not a localized papular variant of lichen planus

BACKGROUND

Lichen nitidus is believed, by some, to be a variant of lichen planus, and by others to be a distinct entity.

OBJECTIVE

We examined five cases of lichen nitidus with immunohistochemical reagents designed to characterize the dermal inflammatory infiltrate in an attempt to resolve the uncertainty.

METHODS

We stained formalin-fixed, paraffin-embedded tissue sections with the following antibodies: L26, A6, KP1, BerH2, OPD4, and HECA-452.

RESULTS

The inflammatory infiltrate was 90% A6+, with few L26+ cells. In contrast to lichen planus, KP1+ macrophages were seen and fewer of the lymphocytes demonstrated HECA-452. Fifty percent to 80% of lymphocytes were OPD4 positive, similar to that usually seen in lichen planus. Rare Ki-1+ cells were seen in one case.

CONCLUSION

We believe that the pattern of a mixed cellular infiltrate characterized by macrophages and a helper T cell response with few HECA-452+ cells is somewhat different from the pattern seen in lichen planus, wherein almost all of the cells are CD4+/HECA-452+ lymphocytes. This suggests a different immunologic pathogenesis.

Punctate keratoses of the palms and soles and keratotic pits of the palmar creases

Punctate keratoses of the palms and soles and keratotic pits of the palmar creases are frequently confused. A prospective study of 283 patients revealed a prevalence of 11% and 3%, respectively, in a metropolitan county hospital dermatology clinic. Punctate keratoses of the palms and soles and keratotic pits of the palmar creases are similar in size, number of lesions per palm, aggravation by trauma, and predominance in blacks and in men. These entities are different in appearance, distribution, age at onset, prevalence, symptoms, and prognosis. Punctate keratosis of the palms and soles and keratotic pits of the palmar creases should be considered independent entities. To help eliminate confusion, we propose that punctate keratoses refer only to the hyperkeratotic papules scattered diffusely in the palms and occasionally in the soles and that keratotic pits of the palmar creases refer only the hyperkeratotic, conical depressions confined to the palmar creases.

Papulosquamous diseases: a review

Papulosquamous diseases are a heterogeneous group of disorders whose etiology primarily is unknown. The nosology of these disorders is based on a descriptive morphology of clinical lesions characterized by scaly papules and plaques. The major entities in this group include psoriasis, parapsoriasis (including pityriasis lichenoides et varioliformis acuta), lichen planus, lichen nitidus, lichen striatus, pityriasis rosea, pityriasis rubra pilaris, seborrheic dermatitis, and the Gianotti-Crosti syndrome. Many other conditions may become papulosquamous and should be considered in the differential diagnosis.

Perforating lichen nitidus

We report a second case of perforating lichen nitidus. This supports the occurrence of the transepidermal elimination phenomenon in lichen nitidus and justifies the addition of lichen nitidus to the family of perforating dermatoses.

Acanthosis nigricans presenting as hyperkeratosis of the palms and soles

A patient with an unusual form of palmoplantar hyperkeratosis is described. On thorough physical examination, widespread acanthosis nigricans was discovered. We believe this patient's distinctive keratoderma represents acanthosis nigricans.