Netherton syndrome (NS) is a rare genodermatosis with an autosomal recessive pattern of inheritance caused by pathogenic variants in the SPINK5 gene. It is characterized by a triad consisting of atopic diathesis, ichthyosis linearis circumflexa, and hair shaft abnormalities. Ichthyosis linearis circumflexa can be confused with atopic dermatitis leading to a delayed diagnosis. Furthermore, difficulty in making the differential diagnosis with other atopiform, erythrodermic, and ichthyosiform entities that exhibit hair shaft abnormalities represent a challenge. Trichoscopy is an accessible and noninvasive auxiliary diagnostic tool in these cases; the hair shaft abnormalities found in NS are bamboo, golf tee, and matchstick hairs. Identification of a pathogenic variant in the SPINK5 gene through genetic testing is necessary to confirm the diagnosis. Multiple treatment options are available including topical therapy with emollients, corticosteroids, calcineurin inhibitors, antiseptics, and narrowband UVB phototherapy. Systemic treatments comprehend intravenous immunoglobulins, and advances in the understanding of the pathophysiology of NS have led to more directed therapies with biologics such as infliximab, ixekizumab, secukinumab, ustekinumab, and dupilumab. Treatments currently under investigation include inhibitors of kallikrein 5, cathelicidins, drugs activating the transcription factor nuclear factor erythroid-derived 2-like 2, and gene therapy using autologous keratinocytes induced with a lentiviral vector encoding SPINK5.

Granuloma gluteale infantum is a rare pediatric dermatological disorder of uncertain etiology. Suggested causes include fluorinated corticosteroids, Candida albicans, and irritant contact dermatitis. We present the case of a 3-year-old boy with recurrent episodes of granuloma gluteale infantum which resolved with treatment of his fecal overflow incontinence. As each recurrence correlated with a relapse of overflow incontinence, in this case the cause was irritant contact dermatitis from the liquid stool. This is the first reported case of recurrent granuloma gluteale infantum.

Angioimmunoblastic T-cell lymphoma (AITL) accounts for 15-20% of all peripheral T-cell lymphomas. It is a rare subtype of CD4 T-cell peripheral lymphoma that affects aged individuals, causing B symptoms, generalized lymphadenopathy and hepatosplenomegaly. Its pathogenesis is still unclear, but in some cases it has been associated with infection, allergic reaction or drug exposure. The majority of patients are diagnosed in an advanced stage and anthracycline based regimen is considered the first-line therapy. Skin involvement is not well characterized, occurring in up to 50% of patients and presenting as nonspecific rash, macules, papules, petechiae, purpura, nodules and urticaria. We present the illustrative case of a 55-year-old woman with an AITL who presented prominent skin findings, arthritis, lymphadenopathy and hypereosinophilia. Skin biopsy reported a T-cell lymphoma and the diagnosis of AITL was confirmed by an axillary lymph node biopsy, which was also positive for Epstein-Barr virus. Chemotherapy with CHOP-21 and thalidomide was given, accomplishing complete remission after six cycles.

Comedones occur when an overproliferation of keratinocytes blocks sebum secretion in a pilosebaceous duct. Comedones have multiple possible etiologies and contributing factors. While comedones are common to acne, they are also seen in occupational exposures and are associated with certain syndromes. We describe a particularly rare case of comedones at the perianus that is not associated with any known exposure or disease and is a rare incidental finding.

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