Exclamation Mark Hairs Research Articles

Alopecia totalis incognito

We report an 11‐year‐old boy with a strong family history of alopecia areata who initially developed alopecia areata with a single circular patch of hair loss on the scalp with exclamation mark hairs at the periphery, which evolved over time into alopecia totalis and then into a novel pattern of hair growth with fine depigmented hair, uniformly 5 mm in length. The hair has not grown any longer over a 48‐month follow‐up period. Scalp biopsies from the occipital scalp demonstrate dense peribulbar lymphocytic infiltrate and uniform miniaturized secondary vellus hairs. This previously undescribed pattern of alopecia areata is remarkable for total lack of alopecia.

Circumscribed scalp hair loss following multiple hair-cutter ant invasion

A 32-year-old woman presented with an abrupt, localized loss of scalp hair that occurred on the previous day. Her nails, skin, and mucosae were normal. On the vertex of the scalp, there was a circular patch of alopecia; the hairs were broken at approximately equal lengths above the skin surface. Several erythematous macules were seen in the affected area, but scale, twisted hair, and exclamation-mark hairs were not present. Further examination revealed the presence of ants on the scalp. This patient is one of several referred to our department presenting with hair loss associated with hair-cutter ant invasion.

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This 34-year-old woman was upset about the persistent bald areas on her scalp which had first developed after the birth of her first child a year earlier. She was finding them difficult to hide, and friends were remarking on the problem. On examination, the underlying scalp appeared completely normal. There were no signs of exclamation mark hairs (short, stumpy hairs with thinning and depigmentation of the hair next to the scalp), but a few white hairs could be seen around the edges.

Ultrastructural study of exclamation‐mark hair shafts in alopecia areata

The prime diagnostic feature of acute alopecia areata is the presence of exclamation mark hairs. These characteristic hairs fracture at their distal end and taper proximally towards the scalp, giving them the appearance of an exclamation mark. Hair morphology was studied in 8 patients with untreated acute alopecia areata and 3 normal adults without hair loss. Light microscopy, transmission and scanning electron microscopy revealed distinct structural differences in the distal end of hairs compared with the remainder of their length and with normal hair shafts. Transverse sections of hairs just below the frayed brush-like tip often displayed asymmetrical cortex disintegration. One side was compact and homogeneous while the other was deeply fissured and/or broken up into discrete heterogeneous-staining fragments of cortical, stratum corneum and cuticular components in addition to apparently degenerate cortex. Many exclamation mark hair tips lacked cuticle and had irregular profiles. Melanin was found in cortical and medullary fragments at the tip, although it was absent in the more degenerate forms of cortex. More proximal sections of these pathognomic telogen hairs revealed nearly normal hair shaft ultrastructure.

Markers of immunologic injury in progressive alopecia areata.

In a selected group of 8 patients with progressive alopecia areata (AA) leading to AA universalis, immunological aspects (in the peripheral blood and the tissue) were studied during the period of the initial attack of the disease. The peripheral T-cell helper/suppressor ratio appeared not to be a reliable parameter for the disease activity. The intrabulbar and peribulbar distribution of T-cells, Langerhans cells and of HLA-DR expression in and around the anagen hair follicles in the progressive areas of the disease (region of exclamation-mark hairs) may suggest a T-cell-mediated injury primarily in the peribulbar regions of the follicles. The data presented tend to support the possibility that in the early development of AA, the dermal pailla (capillary network?) may be the prime target of immunologic injury.

Alopecia areata: alterations in the hair growth cycle and correlation with the follicular pathology.

A histopathological study was performed in 17 patients with alopecia areata to elucidate the changes in hair cycle dynamics. The findings confirm the view that the initial event in alopecia areata is the premature entry of anagen follicles into telogen, although some follicles survive for a time in a dystrophic anagen state. However, after re-entry into anagen takes place, growth appears to be halted in anagen III rather than anagen IV, as has previously been suggested. Follicles then return prematurely to telogen and these truncated cycles are repeated until the disease activity subsides. A new pathogenic hypothesis is presented which relates alterations in hair cycle dynamics to pathological changes within the anagen follicle and also provides an explanation for the formation of exclamation mark hairs and the non-destructive nature of the disease.

Alopecia areata hairs: a scanning electron microscope study.

SUMMARY.— The fractured ends of exclamation mark hairs were found to be quite distinct from those of normal hairs broken by traction when examined with the scanning electron microscope. The cuticular scales of exclamation mark hairs, telogen hairs from around lesions, hairs from unaffected parts of the scalp, and hairs from normal subjects were found to possess smooth edges when first produced. More distally, however, the edges of the scales became jagged, although their configuration remained unaltered, in all cases.