Tumid Lupus Erythematosus Presenting as Patchy Alopecia: A Discussion of Alopecia Associated With Lupus Erythematosus.

Tumid lupus erythematosus (TLE), a subtype of chronic cutaneous lupus erythematosus (CCLE), presents with firm erythematous plaques that lack surface changes such as follicular plugging or scale. These lesions most commonly occur on the face and other photosensitive areas but may also present on the scalp as recurrent circumscribed patches of non-cicatricial alopecia. Including TLE as part of the differential for non-cicatricial alopecia can prove helpful in patients who fail to improve with empiric first-line treatments for more common causes of hair loss. We report a case of TLE that clinically mimicked alopecia areata and seek to highlight the relevant clinical and histological features to promote earlier diagnosis of this entity. A discussion of improved diagnostic and treatment modalities, as well as identifying the uncommon but possible association of TLE with underlying systemic disease, adds to the importance of maintaining clinical suspicion for TLE. Finally, we provide an overview to discriminate TLE from other forms of cutaneous lupus and their unique patterns of alopecia when presenting on the scalp.

Update on protease-activated receptor 2 in cutaneous barrier, differentiation, tumorigenesis and pigmentation, and its role in related dermatologic diseases.

Protease-activated receptor 2 (PAR2) is a transmembrane receptor expressed by multiple tissues, including skin, with rapidly expanding knowledge regarding its roles. In the skin, PAR2 has extensively documented effects in promoting Th2 inflammation and pruritus; and its role in atopic dermatitis continues to be thoroughly studied. Numerous new investigations have shown a more complex range of activities potentially related to dermatologic diseases. Goal of this review is to outline emerging effects of PAR2 activation in the skin other than those related to immunologic and pruritic functions. Specifically, this work seeks to summarize current knowledge (and gaps) of PAR2 as a regulator of epidermal barrier, keratinocyte differentiation, cutaneous tumorigenesis and pigmentation. Additional focus will be placed on possible involvement in dermatologic disease and emergence as a therapeutic target.