Newly described signs in dermatology.

Authors have attempted to discuss recently described "signs" in the field of dermatology.

INTRODUCTION

One of the authors has previously compiled a list of clinical signs in dermatology.[1] Dermatology is an ever-changing branch of clinical medicine. With each passing day, workers make discovery of either new dermatoses, advances in dermatotherapeutics, or new observations in known clinical entities. Keeping this aspect in mind, it is imperative to remain abreast of latest clinical aspects of old and new dermatoses. This article reviews new clinical signs that have been recently described in dermatology.

Ear sign

Tinea capitis is the most common fungal infection among children and must be correctly diagnosed so as to ensure prompt treatment and prevent transmission to a susceptible host. Clinically, it is very much essential to differentiate between tinea capitis and seborrheoea capitis as both of them have a similar clinical profile. In 2012, Agrawal et al. described “Ear sign” in cases of tinea capitis, where one can clinically see the presence of erythematous papules, scaling, or well- to ill-defined papules and plaques over helix, antihelix, and retroauricular region (away from retroauricular fold).[23]

Eyelid sign

Arthropod bite reactions are commonly encountered in the pediatric population; however, identifying the culprit insect is a tough job for the treating dermatologist. Arthropod assault leads to the formation of papules at the site of bite and may vary in its topography; however, the presence of papule and erythema on the eyelids is considered as a proof of bed bug bite in children. Authors have suggested the term “eyelid sign” to describe a bite on the upper eyelid with associated erythema and ipsilateral upper eyelid edema. This “eyelid sign” can be considered as subtle clue to bed bugs as the culprit insect in arthropod assaults on children.[4]

Gulliver's sign

Patients with pyoderma gangrenosum (PG) commonly receive long-term immunosuppressive therapy in high doses than is clinically necessary because clinicians may have difficulty differentiating between active disease and an inactive residual ulcer that is often slow to heal. The inflammatory stage of PG cannot be contained by healing granulation tissue and is characterized by wound edges, which are raised, erythematous, and sometimes necrotic. In contrast, the healing stage of PG shows the edges becoming more even with the surrounding skin and one can make out string-like growths of epithelium, which straddle the border between the ulcer bed and the normal surrounding skin. This transition to healing phase has been termed as Gulliver's sign after the eponymous character in Jonathan Swift's book, Gulliver's Travels. In the book, Gulliver is kept captive by the Lilliputians using stringy ropes. This sign comforts us that inflammation is under control and can be used as a guide to tapering of corticosteroids and other immunosuppressant therapies used in the treatment of PG.[5]

Pink rim sign

In dermoscopy, multiple shades of pink have been described in melanoma without specifying the location of these areas within the lesion. The presence of pink in the periphery or rim of a dermoscopic melanocytic lesion image provides a suspicion of malignancy and is referred to a “pink rim” sign, which is a clue to the dermoscopic diagnosis of invasive melanoma.[6]

Pore sign

Epidermal (epidermoid) cyst can usually be diagnosed clinically as a roughly circular subcutaneous nodule of variable size, of firm consistency, covered by smooth, and normal-colored skin with a central black punctum. The diagnosis of epidermal cyst can easily be made by identifying the punctum, the pore of the follicle from which the cyst has been derived. However, sometimes this pore is not evident, but dermoscopy can aid in visualization of the punctum. The presence of keratin-filled orifice on dermoscopy has been referred to as “pore sign” and is a useful diagnostic feature of epidermal cyst.[7]

Skin crease sign

Pilomatricoma is a relatively common appendageal tumor, which is frequently misdiagnosed as cyst or milia. In majority of cases, a diagnosis of pilomatricoma is made retrospectively on the basis of histopathology. A new sign called as “skin crease sign” has been described to make a preoperative diagnosis of pilomatricoma. It refers to the central longitudinal crease elicited within a lesion when it is squeezed lightly along its margins and perpendicular to the skin tension lines by using the thumbnail of each hand.[8] The anatomic basis for this curious occurrence is not known.

Yoga sign

Yoga refers to the physical, mental, and spiritual practices or regimens that originated in ancient India with a view to attaining a state of mental peace and experiencing one's true self. During performance of yoga, one has to routinely do various exercises and body maneuvers while sitting on the ground. Most of these ground exercises are done whilst sitting cross-legged in the typical “lotus position". The characteristic yoga sitting position on plain and hard floor exerts mechanical stress, that is, repeated and prolonged pressure and shear forces and the skin responds by developing callosities. These callosities (yoga sign) commonly present as hyperkeratotic, circumscribed, hyperpigmented plaques on the outer ankles and fifth toes.[9] However; such callosities are present in a lot of the Indian population due to their cultural habits - sitting cross-legged (for activities such as eating, cooking, praying, and so on). These activities are much more common causes of callosities rather than the actual practice of yoga asana.