Alopecia Areata
Alopecia areata (AA) is a chronic, non-scarring autoimmune disease in which hair suddenly falls out, leaving sharply defined round or oval bald patches on the scalp or any hair-bearing area of the body. It can affect men and women of any age, and because it can change a person's appearance so quickly, it often comes as a serious emotional shock.
At its core, alopecia areata is a collapse of the hair follicle's immune privilege:
- Loss of immune privilege during anagen: Normally, growing (anagen) follicles are shielded from immune recognition because they suppress antigen display, with reduced MHC class I/II expression and increased release of immunosuppressive molecules such as TGF-beta and alpha-MSH. When this protection breaks down, the immune system starts treating the follicle as foreign.
- Autoreactive T cells around the follicle: Autoreactive CD8+ (NKG2D+) T lymphocytes mistakenly target follicular self-antigens (such as melanocyte-associated antigens) and cluster tightly around the base of the follicle, producing the "swarm of bees" picture seen on histology (swarm of bees).
- The JAK-STAT pathway: CD8+ T cells and natural killer (NK) cells release potent inflammatory cytokines, notably interferon-gamma (IFN-gamma) and interleukin-15 (IL-15). These act on follicular epithelial cells through JAK-STAT signaling (particularly JAK1, JAK2 and JAK3), setting up a self-sustaining inflammatory loop that halts hair growth and pushes the follicle prematurely into its regressing phases (catagen/telogen).
- Triggers and genetics: Inheritance is complex and polygenic, involving genes such as HLA, IL2RA and CTLA4. Environmental factors such as acute psychosocial stress, viral infections or microtrauma can act as the spark that sets off the autoimmune attack.
At Haute-Derma, we treat alopecia areata as a condition that needs prompt medical care: the goals are to switch off the autoimmune attack, protect dermal papillae that are not yet permanently damaged, and get hair growing again as quickly as possible.
Clinical Features and Differential Diagnosis
Alopecia areata is recognized by characteristic changes on the scalp and, in some patients, the nails:
- Typical patches: One or more well-defined round or oval bald patches appear suddenly. The skin inside is completely smooth, with no redness, scaling or scarring.
- Signs of an active, spreading edge:
- Positive hair pull test at the margin: Hairs at the edge of the patch come out very easily, showing that the inflammation is spreading.
- Exclamation mark hairs: Short hairs (3–4 mm) at the margin with a thick, dark tip and a thin, pale base near the scalp.
- Trichoscopy (scalp dermoscopy) findings:
- Yellow dots: keratin and sebum building up in empty follicular openings.
- Black dots: hairs broken off right at the skin surface.
- Pigtail hairs or fine white regrowing vellus hairs: signs that the follicles are recovering.
- Nail changes: Seen in 10–20% of patients, typically as fine pitting, longitudinal ridging (trachyonychia) or brittle nails. Nail involvement often signals a more severe course.
How Haute-Derma Diagnoses and Treats Alopecia Areata
- Trichoscopy and SALT scoring: We examine the scalp with a high-magnification dermatoscope/trichoscope to look for signs of active disease (exclamation mark hairs, black dots). Severity is scored with the SALT (Severity of Alopecia Tool) to classify hair loss as under 25%, 25–50% or over 50% of the scalp.
- Local treatment to calm the autoimmune attack:
- Intralesional triamcinolone acetonide (ILTAC): The gold standard for limited patchy disease (< 50% of the scalp). Triamcinolone is injected directly into the deep dermis at the edge and center of each patch to suppress the autoreactive T cells.
- High-potency topical corticosteroids (clobetasol propionate): Applied as a cream or foam, sometimes under occlusion.
- Adding minoxidil 5%: Used as a supporting treatment once inflammation is under control, to improve the microcirculation that feeds the follicles.
- Systemic treatment and newer JAK inhibitors:
- For severe, rapidly progressing forms (alopecia totalis/universalis), we work with other specialists to prescribe intermittent high-dose systemic corticosteroids (pulse therapy).
- JAK inhibitors: Modern targeted drugs such as baricitinib, ritlecitinib or tofacitinib block JAK signaling (JAK1, JAK2 or JAK3, depending on the drug) and dampen the IFN-gamma-driven attack. They produce meaningful regrowth in many patients, including some with complete scalp hair loss.
- Light-based therapy and scalp care:
- 308 nm excimer laser / narrowband UVB (NB-UVB): Induces apoptosis (programmed cell death) of autoreactive T cells around the follicles without systemic effects.
- We advise on a gentle scalp-care routine and stress management, and schedule regular follow-up visits to track follicle recovery closely.
Common Types of Alopecia Areata
| Type / Classification | Mechanism and Clinical Features |
|---|---|
| Patchy alopecia areata | The most common form. One or a few separate round or oval bald patches on the scalp or beard area. Best outlook for recovery. |
| Ophiasis pattern | Hair loss forms a winding band along the nape and around both ears. This form is often treatment-resistant and responds less well. |
| Alopecia totalis (AT) | The autoimmune attack spreads until all scalp hair is lost, with no hairs remaining. |
| Alopecia universalis (AU) | The most severe form. Complete loss of scalp hair along with the eyelashes, eyebrows, underarm, pubic and body hair. |
