They are both "hair loss", and that is roughly where the similarity ends.
Androgenetic alopecia — pattern hair loss
Driven by genetic sensitivity to DHT. Follicles gradually miniaturise, producing finer, shorter hairs until they stop producing visible hair at all. It is slow, predictable in pattern, and progressive.
Alopecia areata
An autoimmune condition. The immune system attacks hair follicles, causing inflammation and hair loss. It typically appears as discrete round or oval patches of complete hair loss with normal-looking skin, and it can occur anywhere hair grows — scalp, beard, eyebrows, eyelashes, body.
How to Tell Them Apart
- Pattern: receding hairline and crown thinning in men, diffuse widening of the parting in women, versus discrete patches of total loss
- Speed: years, versus weeks
- Completeness: thinning, versus smooth bald patches with no hair at all
- Location: scalp only, versus potentially eyebrows, lashes and beard
- Course: steadily progressive, versus unpredictable — alopecia areata can regrow spontaneously and relapse
Alopecia areata can also affect nails, producing pitting or ridging. That is a useful clue and one people rarely think to look for.
Why It Matters So Much
Because the treatments do not overlap at all.
Finasteride and dutasteride reduce DHT. Alopecia areata has nothing to do with DHT, so they do nothing for it. Minoxidil is sometimes used but is not a treatment for the underlying autoimmune process.
Conversely, the newer treatments for severe alopecia areata — JAK inhibitors such as ritlecitinib and baricitinib — target immune signalling. They are not treatments for pattern baldness.
Someone with alopecia areata buying finasteride online is spending money on the wrong disease. It is a common and entirely understandable mistake, because the online market for hair loss is built almost exclusively around pattern loss.
The NHS Position Differs Too
Male pattern baldness is treated as cosmetic, so finasteride for hair loss is not routinely available on the NHS.
Alopecia areata is a medical condition. NICE has recommended ritlecitinib for severe alopecia areata in people aged 12 and over — the first medicine for the condition recommended for NHS use, estimated to benefit up to 14,000 people in England. That is an NHS route that simply does not exist for pattern loss.
Other Causes Worth Ruling Out
Neither diagnosis is automatic. Also consider:
- Telogen effluvium — diffuse shedding a few months after illness, surgery, childbirth, severe stress or rapid weight loss. Usually temporary.
- Scarring alopecias, where the follicle is destroyed. Early diagnosis matters because the damage is permanent.
- Thyroid disease, iron deficiency and other systemic causes.
- Traction alopecia from tight hairstyles.
What to Do
If your hair loss is patchy, sudden, affects eyebrows or beard, or has come with nail changes, see a GP rather than an online hair-loss service. Those services are configured to diagnose and treat one condition, and a form designed around pattern loss will not catch what you have.
If it is a slow, symmetrical, patterned recession over years, pattern hair loss is the likely explanation and the usual treatments apply.