GAGS is clinical tool for assessing the severity of acne vulgaris that was first proposed by Doshi et al in 1997.
Acne lesions can be divided into the following in terms of increasing severity:
- Comedones – blackheads and whiteheads
- Papules are inflamed bumps less than 1 cm in size
- Pustules are papules with a head of pus (pusheads)
- Nodules/cysts are bumps that are 1 cm or larger in size. Nodules are solid whereas cysts are fluid-filled
Six locations on the face and chest/upper back are graded according to the most severe lesion present, for example:
| Location | Type of lesion | Most severe lesion |
| Forehead | Comedones | Comedones |
| Right cheek | Comedones, papules | Papules |
| Left cheek | Papules, pustules | Pustules |
| Nose | Papules, nodules | Nodules/cysts |
| Chin | Papules, pustules, cysts | Nodules/cysts |
| Chest/upper back | Comedones, papules, pustules, nodules/cysts | Nodules/cysts |
Now that you know how to determine the most severe acne lesion, you can start using our GAGS calculator by clicking the link below:
We hope you’ll find our calculator useful for monitoring the effectiveness of your acne treatment.
Atopic Dermatitis (Eczema):
- EASI (Eczema Area and Severity Index) for patients aged 8 years and above – for professional use
- EASI (Eczema Area and Severity Index) calculator for patients under 8 years of age – for professional use
- SCORAD (SCORing Atopic Dermatitis) – for professional use
- POEM (Patient Oriented Eczema Measure) is a simple assessment tool developed by the University of Nottingham for patients to assess the severity of their eczema (Atopic Dermatitis)
Melasma
- MASI (Melasma Area and Severity Index) – for professional use
- mMASI (modified Melasma Area and Severity Index) – for professional use
Psoriasis
- PASI (Psoriasis Area and Severity Index) – for professional use
Skin type
- Fitzpatrick skin type – for professional and patient use